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Showing 1-20 of about 51 results.
Two-component Jets of GRB 160623A as Shocked Jet Cocoon AfterglowChen, Wei JuUrata, YujiHuang, KuiyunTakahashi, SatokoPetitpas, GlenAsada, KeiichiDOI: info:10.3847/2041-8213/ab76d4v. 891L15
Chen, Wei Ju, Urata, Yuji, Huang, Kuiyun, Takahashi, Satoko, Petitpas, Glen, and Asada, Keiichi. 2020. "Two-component Jets of GRB 160623A as Shocked Jet Cocoon Afterglow." The Astrophysical Journal 891:L15.
ID: 156338
Type: article
Authors: Chen, Wei Ju; Urata, Yuji; Huang, Kuiyun; Takahashi, Satoko; Petitpas, Glen; Asada, Keiichi
Abstract: Two components of jets associated with the afterglow of the gamma-ray burst (GRB) 160623A were observed with multifrequency observations including long-term monitoring in a submillimeter range (230 GHz) using the Submillimeter Array. The observed light curves with temporal breaks suggest on the basis of the standard forward-shock synchrotron-radiation model that the X-ray radiation is narrowly collimated with an opening angle θ_{n,j}<∼ 6°, whereas the radio radiation originated from wider jets (∼27°). The temporal and spectral evolutions of the radio afterglow agree with those expected from a synchrotron-radiation modeling with typical physical parameters, except for the fact that the observed wide jet opening angle for the radio emission is significantly larger than the theoretical maximum opening angle. By contrast, the opening angle of the X-ray afterglow is consistent with the typical value of GRB jets. Since the theory of the relativistic cocoon afterglow emission is similar to that of a regular afterglow with an opening angle of ∼30°, the observed radio emission can be interpreted as the shocked jet cocoon emission. This result therefore indicates that the two components of the jets observed in the GRB 160623A afterglow are caused by the jet and the shocked jet cocoon afterglows.
First Resolved Dust Continuum Measurements of Individual Giant Molecular Clouds in the Andromeda GalaxyForbrich, JanLada, Charles J.Viaene, SébastienPetitpas, GlenDOI: info:10.3847/1538-4357/ab68dev. 89042
Forbrich, Jan, Lada, Charles J., Viaene, Sébastien, and Petitpas, Glen. 2020. "First Resolved Dust Continuum Measurements of Individual Giant Molecular Clouds in the Andromeda Galaxy." The Astrophysical Journal 890:42.
ID: 157600
Type: article
Authors: Forbrich, Jan; Lada, Charles J.; Viaene, Sébastien; Petitpas, Glen
Abstract: In our local Galactic neighborhood, molecular clouds are best studied using a combination of dust measurements, to determine robust masses, sizes, and internal structures of the clouds, and molecular-line observations to determine cloud kinematics and chemistry. We present here the first results of a program designed to extend such studies to nearby galaxies beyond the Magellanic Clouds. Utilizing the wideband upgrade of the Submillimeter Array (SMA) at 230 GHz, we have obtained the first continuum detections of the thermal dust emission on sub-GMC scales (∼15 pc) within the Andromeda galaxy (M31). These include the first resolved continuum detections of dust emission from individual giant molecular clouds (GMCs) beyond the Magellanic Clouds. Utilizing a powerful capability of the SMA, we simultaneously recorded CO(2-1) emission with identical (u, V) coverage, astrometry, and calibration, enabling the first measurements of the CO conversion factor, αCO(2-1), toward individual GMCs across an external galaxy. Our direct measurement yields an average CO-to-dust mass conversion factor of ${\alpha }_{\mathrm{CO}-\mathrm{dust}}^{{\prime} }=0.042\pm 0.018$ M (K km s-1 pc2)-1 for the J = 2-1 transition. This value does not appear to vary with galactocentric radius. Assuming a constant gas-to-dust ratio of 136, the resulting αCO = 5.7 ± 2.4 M (K km s-1 pc2)-1 for the 2-1 transition is in excellent agreement with that of GMCs in the Milky Way, given the uncertainties. Finally, using the same analysis techniques, we compare our results with observations of the local Orion molecular clouds, placed at the distance of M31 and simulated to appear as they would if observed by the SMA.
Erratum: 'First Resolved Dust Continuum Measurements of Individual Giant Molecular Clouds in the Andromeda Galaxy' (2020, ApJ, 890, 42)Forbrich, JanLada, Charles J.Viaene, SébastienPetitpas, GlenDOI: info:10.3847/1538-4357/abb371v. 900196
Forbrich, Jan, Lada, Charles J., Viaene, Sébastien, and Petitpas, Glen. 2020. "Erratum: "First Resolved Dust Continuum Measurements of Individual Giant Molecular Clouds in the Andromeda Galaxy" (2020, ApJ, 890, 42)." The Astrophysical Journal 900:196.
ID: 158020
Type: article
Authors: Forbrich, Jan; Lada, Charles J.; Viaene, Sébastien; Petitpas, Glen
The nature of 500 micron risers I: SMA observationsGreenslade, J.Clements, D. L.Petitpas, GlenAsboth, V.Conley, A.Pérez-Fournon, I.Riechers, D.DOI: info:10.1093/mnras/staa1637v. 4962315–2333
Greenslade, J., Clements, D. L., Petitpas, Glen, Asboth, V., Conley, A., Pérez-Fournon, I., and Riechers, D. 2020. "The nature of 500 micron risers I: SMA observations." Monthly Notices of the Royal Astronomical Society 496:2315– 2333.
ID: 157849
Type: article
Authors: Greenslade, J.; Clements, D. L.; Petitpas, Glen; Asboth, V.; Conley, A.; Pérez-Fournon, I.; Riechers, D.
Abstract: We present SMA observations at resolutions from 0.35 to 3 arcsec of a sample of 34 candidate high redshift dusty star forming galaxies (DSFGs). These sources were selected from the HerMES Herschel survey catalogues to have SEDs rising from 250 to 350 to 500 μm, a population termed 500-risers. We detect counterparts to 24 of these sources, with four having two counterparts. We conclude that the remaining ten sources that lack detected counterparts are likely to have three or more associated sources which blend together to produce the observed Herschel source. We examine the role of lensing, which is predicted to dominate the brightest (F500 > 60 mJy) half of our sample. We find that while lensing plays a role, at least 35 per cent of the bright sources are likely to be multiple sources rather than the result of lensing. At fainter fluxes we find a blending rate comparable to, or greater than, the predicted 40 per cent. We determine far-IR luminosities and star formation rates for the non-multiple sources in our sample and conclude that, in the absence of strong lensing, our 500-risers are very luminous systems with LFIR > 1013 L and star formation rates >1000 M yr-1.
A SCUBA-2 selected Herschel-SPIRE dropout and the nature of this populationGreenslade, J.Aguilar, E.Clements, D. L.Dannerbauer, H.Cheng, T.Petitpas, GlenYang, C.Messias, H.Oteo, I.Farrah, D.Michałowski, M. J.Pérez Fournon, I.Aretxaga, I.Yun, M. S.Eales, S.Dunne, L.Cooray, A.Andreani, P.Hughes, D. H.Velázquez, M.Sánchez-Argüelles, D.Ponthieu, N.DOI: info:10.1093/mnras/stz2850v. 4905317–5334
Greenslade, J., Aguilar, E., Clements, D. L., Dannerbauer, H., Cheng, T., Petitpas, Glen, Yang, C., Messias, H., Oteo, I., Farrah, D., Michałowski, M. J., Pérez Fournon, I., Aretxaga, I., Yun, M. S., Eales, S., Dunne, L., Cooray, A., Andreani, P., Hughes, D. H., Velázquez, M., Sánchez-Argüelles, D., and Ponthieu, N. 2019. "A SCUBA-2 selected Herschel-SPIRE dropout and the nature of this population." Monthly Notices of the Royal Astronomical Society 490:5317– 5334.
ID: 154512
Type: article
Authors: Greenslade, J.; Aguilar, E.; Clements, D. L.; Dannerbauer, H.; Cheng, T.; Petitpas, Glen; Yang, C.; Messias, H.; Oteo, I.; Farrah, D.; Michałowski, M. J.; Pérez Fournon, I.; Aretxaga, I.; Yun, M. S.; Eales, S.; Dunne, L.; Cooray, A.; Andreani, P.; Hughes, D. H.; Velázquez, M.; Sánchez-Argüelles, D.; Ponthieu, N.
Abstract: Dusty star-forming galaxies (DSFGs) detected at z > 4 provide important examples of the first generations of massive galaxies. However, few examples with spectroscopic confirmation are currently known, with Hershel struggling to detect significant numbers of z > 6 DSFGs. NGP6_D1 is a bright 850 μm source (12.3 ± 2.5 mJy) with no counterparts at shorter wavelengths (a SPIRE dropout). Interferometric observations confirm it is a single source, with no evidence for any optical or NIR emission, or nearby likely foreground lensing sources. No >3σ detected lines are seen in both LMT Redshift Search Receiver and IRAM 30 m EMIR spectra of NGP6_D1 across 32 GHz of bandwidth despite reaching detection limits of ̃ 1 mJy/500 km s^{-1}, so the redshift remains unknown. Template fitting suggests that NGP6_D1 is most likely between z = 5.8 and 8.3. SED analysis finds that NGP6_D1 is a ULIRG, with a dust mass ̃108-109 M and a star-formation rate of ̃500 M yr-1. We place upper limits on the gas mass of NGP6_D1 of MH2 11 M, consistent with a gas-to-dust ratio of ̃100-1000. We discuss the nature of NGP6_D1 in the context of the broader sub-mm population, and find that comparable SPIRE dropouts account for ̃20 per cent of all SCUBA-2 detected sources, but with a similar flux density distribution to the general population.
Evidence for Late-stage Eruptive Mass Loss in the Progenitor to SN2018gep, a Broad-lined Ic Supernova: Pre-explosion Emission and a Rapidly Rising Luminous TransientHo, Anna Y. Q.Goldstein, Daniel A.Schulze, SteveKhatami, David K.Perley, Daniel A.Ergon, MattiasGal-yam, AvishayCorsi, AlessandraAndreoni, IgorBarbarino, CristinaBellm, Eric C.Blagorodnova, NadiaBright, Joe S.Burns, E.Cenko, S. BradleyCunningham, VirginiaDe, KishalayDekany, RichardDugas, AlisonFender, Rob P.Fransson, ClaesFremling, ChristofferGoldstein, AdamGraham, Matthew J.Hale, DavidHoresh, AssafHung, TiaraKasliwal, Mansi M.Kuin, N. Paul M.Kulkarni, S. R.Kupfer, ThomasLunnan, RagnhildMasci, Frank J.Ngeow, Chow-ChoongNugent, Peter E.Ofek, Eran O.Patterson, Maria T.Petitpas, GlenRusholme, BenSai, HannaSfaradi, ItaiShupe, David L.Sollerman, JesperSoumagnac, Maayane T.Tachibana, YutaroTaddia, FrancescoWalters, RichardWang, XiaofengYao, YuhanZhang, XinhanDOI: info:10.3847/1538-4357/ab55ecv. 887169
Ho, Anna Y. Q., Goldstein, Daniel A., Schulze, Steve, Khatami, David K., Perley, Daniel A., Ergon, Mattias, Gal-yam, Avishay, Corsi, Alessandra, Andreoni, Igor, Barbarino, Cristina, Bellm, Eric C., Blagorodnova, Nadia, Bright, Joe S., Burns, E., Cenko, S. Bradley, Cunningham, Virginia, De, Kishalay, Dekany, Richard, Dugas, Alison, Fender, Rob P., Fransson, Claes, Fremling, Christoffer, Goldstein, Adam, Graham, Matthew J., Hale, David et al. 2019. "Evidence for Late-stage Eruptive Mass Loss in the Progenitor to SN2018gep, a Broad-lined Ic Supernova: Pre-explosion Emission and a Rapidly Rising Luminous Transient." The Astrophysical Journal 887:169.
ID: 154546
Type: article
Authors: Ho, Anna Y. Q.; Goldstein, Daniel A.; Schulze, Steve; Khatami, David K.; Perley, Daniel A.; Ergon, Mattias; Gal-yam, Avishay; Corsi, Alessandra; Andreoni, Igor; Barbarino, Cristina; Bellm, Eric C.; Blagorodnova, Nadia; Bright, Joe S.; Burns, E.; Cenko, S. Bradley; Cunningham, Virginia; De, Kishalay; Dekany, Richard; Dugas, Alison; Fender, Rob P.; Fransson, Claes; Fremling, Christoffer; Goldstein, Adam; Graham, Matthew J.; Hale, David; Horesh, Assaf; Hung, Tiara; Kasliwal, Mansi M.; Kuin, N. Paul M.; Kulkarni, S. R.; Kupfer, Thomas; Lunnan, Ragnhild; Masci, Frank J.; Ngeow, Chow-Choong; Nugent, Peter E.; Ofek, Eran O.; Patterson, Maria T.; Petitpas, Glen; Rusholme, Ben; Sai, Hanna; Sfaradi, Itai; Shupe, David L.; Sollerman, Jesper; Soumagnac, Maayane T.; Tachibana, Yutaro; Taddia, Francesco; Walters, Richard; Wang, Xiaofeng; Yao, Yuhan; Zhang, Xinhan
Abstract: We present detailed observations of ZTF18abukavn (SN2018gep), discovered in high-cadence data from the Zwicky Transient Facility as a rapidly rising (1.4 ± 0.1 mag hr−1) and luminous ({M}g,{peak}=-20 mag) transient. It is spectroscopically classified as a broad-lined stripped-envelope supernova (Ic-BL SN). The high peak luminosity ({L}bol}≳ 3× {10}44 {erg} {{{s}}}-1), the short rise time ({t}rise}=3 {days} in g band), and the blue colors at peak (g{--}r∼ -0.4) all resemble the high-redshift Ic-BL iPTF16asu, as well as several other unclassified fast transients. The early discovery of SN2018gep (within an hour of shock breakout) enabled an intensive spectroscopic campaign, including the highest-temperature ({T}eff}≳ {{40,000}} {{K}}) spectra of a stripped-envelope SN. A retrospective search revealed luminous ({M}g∼ {M}r≈ -14 mag) emission in the days to weeks before explosion, the first definitive detection of precursor emission for a Ic-BL. We find a limit on the isotropic gamma-ray energy release {E}γ ,{iso}}48 {erg}, a limit on X-ray emission {L}{{X}}}}40 {erg} {{{s}}}-1, and a limit on radio emission ν {L}ν ≲ {10}37 {erg} {{{s}}}-1. Taken together, we find that the early (. Taken together, we find that the early (ȯ ) at large radii (3× {10}14 {cm}) that was ejected in eruptive pre-explosion mass-loss episodes. The late-time (> 10 {days}) light curve requires an additional energy source, which could be the radioactive decay of Ni-56.
AT2018cow: A Luminous Millimeter TransientHo, Anna Y. Q.Phinney, E. SterlRavi, VikramKulkarni, S. R.Petitpas, GlenEmonts, BjornBhalerao, V.Blundell, RayCenko, S. BradleyDobie, DougalHowie, RyanKamraj, NikitaKasliwal, Mansi M.Murphy, TaraPerley, Daniel A.Sridharan, T. K.Yoon, IlsangDOI: info:10.3847/1538-4357/aaf473v. 87173
Ho, Anna Y. Q., Phinney, E. Sterl, Ravi, Vikram, Kulkarni, S. R., Petitpas, Glen, Emonts, Bjorn, Bhalerao, V., Blundell, Ray, Cenko, S. Bradley, Dobie, Dougal, Howie, Ryan, Kamraj, Nikita, Kasliwal, Mansi M., Murphy, Tara, Perley, Daniel A., Sridharan, T. K., and Yoon, Ilsang. 2019. "AT2018cow: A Luminous Millimeter Transient." The Astrophysical Journal 871:73.
ID: 150435
Type: article
Authors: Ho, Anna Y. Q.; Phinney, E. Sterl; Ravi, Vikram; Kulkarni, S. R.; Petitpas, Glen; Emonts, Bjorn; Bhalerao, V.; Blundell, Ray; Cenko, S. Bradley; Dobie, Dougal; Howie, Ryan; Kamraj, Nikita; Kasliwal, Mansi M.; Murphy, Tara; Perley, Daniel A.; Sridharan, T. K.; Yoon, Ilsang
Abstract: We present detailed submillimeter- through centimeter-wave observations of the extraordinary extragalactic transient AT2018cow. The apparent characteristics—the high radio luminosity, the rise and long-lived emission plateau at millimeter bands, and the sub-relativistic velocity—have no precedent. A basic interpretation of the data suggests {E}k≳ 4 × {10}48 {erg} coupled to a fast but sub-relativistic (v≈ 0.13c) shock in a dense ({n}e≈ 3 × {10}5 {cm}}-3) medium. We find that the X-ray emission is not naturally explained by an extension of the radio-submm synchrotron spectrum, nor by inverse Compton scattering of the dominant blackbody UV/optical/IR photons by energetic electrons within the forward shock. By {{Δ }}t≈ 20 {days}, the X-ray emission shows spectral softening and erratic inter-day variability. Taken together, we are led to invoke an additional source of X-ray emission: the central engine of the event. Regardless of the nature of this central engine, this source heralds a new class of energetic transients shocking a dense medium, which at early times are most readily observed at millimeter wavelengths.
ALMA Polarimetry of AT2018cowHuang, KuiyunShimoda, JiroUrata, YujiToma, KenjiYamaoka, KazutakaAsada, KeiichiNagai, HiroshiTakahashi, SatokoPetitpas, GlenTashiro, MakotoDOI: info:10.3847/2041-8213/ab23fdv. 878L25
Huang, Kuiyun, Shimoda, Jiro, Urata, Yuji, Toma, Kenji, Yamaoka, Kazutaka, Asada, Keiichi, Nagai, Hiroshi, Takahashi, Satoko, Petitpas, Glen, and Tashiro, Makoto. 2019. "ALMA Polarimetry of AT2018cow." Astrophysical Journal Letters 878:L25.
ID: 152911
Type: article
Authors: Huang, Kuiyun; Shimoda, Jiro; Urata, Yuji; Toma, Kenji; Yamaoka, Kazutaka; Asada, Keiichi; Nagai, Hiroshi; Takahashi, Satoko; Petitpas, Glen; Tashiro, Makoto
Abstract: We present the first radio polarimetric observations of a fast-rising blue optical transient, AT2018cow. Two epochs of polarimetry with additional coincident photometry were performed with the Atacama Large Millimeter/submillimeter Array. The overall photometric results based on simultaneous observations in the 100 and 230 GHz bands are consistent with the nonthermal radiation model reported by Ho et al. and indicate that the spectral peaks (∼110 GHz at the first epoch and ∼67 GHz at the second epoch) represent the synchrotron self-absorption frequency. The non-detection of linear polarization with <0.15% in the 230 GHz band at the phase when the effect of synchrotron self-absorption was quite small in the band may be explained by internal Faraday depolarization with high circumburst density and strong magnetic field. This result supports the stellar explosion scenario rather than the tidal disruption model. The maximum energy of accelerating particles at the shocks of AT2018cow-like objects is also discussed.
First Detection of Radio Linear Polarization in a Gamma-Ray Burst AfterglowUrata, YujiToma, KenjiHuang, KuiyunAsada, KeiichiNagai, HiroshiTakahashi, SatokoPetitpas, GlenTashiro, MakotoYamaoka, KazutakaDOI: info:10.3847/2041-8213/ab48f3v. 884L58
Urata, Yuji, Toma, Kenji, Huang, Kuiyun, Asada, Keiichi, Nagai, Hiroshi, Takahashi, Satoko, Petitpas, Glen, Tashiro, Makoto, and Yamaoka, Kazutaka. 2019. "First Detection of Radio Linear Polarization in a Gamma-Ray Burst Afterglow." The Astrophysical Journal 884:L58.
ID: 154622
Type: article
Authors: Urata, Yuji; Toma, Kenji; Huang, Kuiyun; Asada, Keiichi; Nagai, Hiroshi; Takahashi, Satoko; Petitpas, Glen; Tashiro, Makoto; Yamaoka, Kazutaka
Abstract: We report the first detection of radio polarization of a gamma-ray burst (GRB) afterglow with the first intensive combined use of telescopes in the millimeter and submillimeter ranges for GRB 171205A. The linear polarization degree in the millimeter band at the subpercent level (0.27% ± 0.04%) is lower than those observed in late-time optical afterglows (weighted average of ̃1%). The Faraday depolarization by nonaccelerated, cool electrons in the shocked region is one of the possible mechanisms for the low value. This scenario requires a total energy that is larger by a factor of ̃10 than ordinary estimates without considering nonaccelerated electrons. The polarization position angle varies by at least 20° across the millimeter band, which is not inconsistent with this scenario. This result indicates that polarimetry in the millimeter and submillimeter ranges is a unique tool for investigating GRB energetics, and coincident observations with multiple frequencies or bands would provide more accurate measurements of the nonaccelerated electron fraction.
The luminous host galaxy, faint supernova and rapid afterglow rebrightening of GRB 100418Ade Ugarte Postigo, A.Thöne, C. C.Bensch, K.van der Horst, A. J.Kann, D. A.Cano, Z.Izzo, L.Goldoni, P.Martín, S.Filgas, R.Schady, P.Gorosabel, J.Bikmaev, I.Bremer, M.Burenin, R.Castro-Tirado, A. J.Covino, S.Fynbo, J. P. U.Garcia-Appadoo, D.De Gregorio-Monsalvo, I.Jelínek, M.Khamitov, I.Kamble, AtishKouveliotou, C.Krühler, T.Leloudas, G.Melnikov, S.Nardini, M.Perley, D. A.Petitpas, GlenPooley, G.Rau, A.Rol, E.Sánchez-Ramírez, R.Starling, R. L. C.Tanvir, N. R.Wiersema, K.Wijers, R. A. M. J.Zafar, T.DOI: info:10.1051/0004-6361/201833636v. 620A190
de Ugarte Postigo, A., Thöne, C. C., Bensch, K., van der Horst, A. J., Kann, D. A., Cano, Z., Izzo, L., Goldoni, P., Martín, S., Filgas, R., Schady, P., Gorosabel, J., Bikmaev, I., Bremer, M., Burenin, R., Castro-Tirado, A. J., Covino, S., Fynbo, J. P. U., Garcia-Appadoo, D., De Gregorio-Monsalvo, I., Jelínek, M., Khamitov, I., Kamble, Atish, Kouveliotou, C., Krühler, T. et al. 2018. "The luminous host galaxy, faint supernova and rapid afterglow rebrightening of GRB 100418A." Astronomy and Astrophysics 620:A190.
ID: 150183
Type: article
Authors: de Ugarte Postigo, A.; Thöne, C. C.; Bensch, K.; van der Horst, A. J.; Kann, D. A.; Cano, Z.; Izzo, L.; Goldoni, P.; Martín, S.; Filgas, R.; Schady, P.; Gorosabel, J.; Bikmaev, I.; Bremer, M.; Burenin, R.; Castro-Tirado, A. J.; Covino, S.; Fynbo, J. P. U.; Garcia-Appadoo, D.; De Gregorio-Monsalvo, I.; Jelínek, M.; Khamitov, I.; Kamble, Atish; Kouveliotou, C.; Krühler, T.; Leloudas, G.; Melnikov, S.; Nardini, M.; Perley, D. A.; Petitpas, Glen; Pooley, G.; Rau, A.; Rol, E.; Sánchez-Ramírez, R.; Starling, R. L. C.; Tanvir, N. R.; Wiersema, K.; Wijers, R. A. M. J.; Zafar, T.
Abstract: Context. Long gamma-ray bursts (GRBs) give us the chance to study both their extreme physics and the star-forming galaxies in which they form. Aims: GRB 100418A, at a redshift of z = 0.6239, had a bright optical and radio afterglow, and a luminous star-forming host galaxy. This allowed us to study the radiation of the explosion as well as the interstellar medium of the host both in absorption and emission. Methods: We collected photometric data from radio to X-ray wavelengths to study the evolution of the afterglow and the contribution of a possible supernova (SN) and three X-shooter spectra obtained during the first 60 h. Results: The light curve shows a very fast optical rebrightening, with an amplitude of ˜3 magnitudes, starting 2.4 h after the GRB onset. This cannot be explained by a standard external shock model and requires other contributions, such as late central-engine activity. Two weeks after the burst we detect an excess in the light curve consistent with a SN with peak absolute magnitude MV = -18.5 mag, among the faintest GRB-SNe detected to date. The host galaxy shows two components in emission, with velocities differing by 130 km s-1, but otherwise having similar properties. While some absorption and emission components coincide, the absorbing gas spans much higher velocities, indicating the presence of gas beyond the star-forming regions. The host has a star formation rate of SFR = 12.2 M yr-1, a metallicity of 12 + log(O/H) = 8.55, and a mass of 1.6 × 109 M. Conclusions: GRB 100418A is a member of a class of afterglow light curves which show a steep rebrightening in the optical during the first day, which cannot be explained by traditional models. Its very faint associated SN shows that GRB-SNe can have a larger dispersion in luminosities than previously seen. Furthermore, we have obtained a complete view of the host of GRB 100418A owing to its spectrum, which contains a remarkable number of both emission and absorption lines. This work makes use of data obtained at the following telescopes/observatories: VLT/Paranal (proposals 085.A-0009, 085.D-0773), GTC/ORM (proposals GTC74-10A, GTCMULTIPLE2B-17A), Keck/MK, Subaru/MK, 3.5m/CAHA, UKIRT/MK, WHT/ORM, RTT150/TUBITAK, Spitzer, PdBI/IRAM, WSRT/RO, Ryle/MRAO, and SMA/MK.
Observational constraints on the physical nature of submillimetre source multiplicity: chance projections are commonHayward, Christopher C.Chapman, Scott C.Steidel, Charles C.Golob, AnneyaCasey, Caitlin M.Smith, Daniel J. B.Zitrin, AdiBlain, Andrew W.Bremer, Malcolm N.Chen, Chian-ChouCoppin, Kristen E. K.Farrah, DuncanIbar, EduardoMichalowski, Michal J.Sawicki, MarcinScott, Douglasvan der Werf, PaulFazio, Giovanni G.Geach, James E.Gurwell, MarkPetitpas, GlenWilner, David J.DOI: info:10.1093/mnras/sty304v. 4762278–2287
Hayward, Christopher C., Chapman, Scott C., Steidel, Charles C., Golob, Anneya, Casey, Caitlin M., Smith, Daniel J. B., Zitrin, Adi, Blain, Andrew W., Bremer, Malcolm N., Chen, Chian-Chou, Coppin, Kristen E. K., Farrah, Duncan, Ibar, Eduardo, Michalowski, Michal J., Sawicki, Marcin, Scott, Douglas, van der Werf, Paul, Fazio, Giovanni G., Geach, James E., Gurwell, Mark, Petitpas, Glen, and Wilner, David J. 2018. "Observational constraints on the physical nature of submillimetre source multiplicity: chance projections are common." Monthly Notices of the Royal Astronomical Society 476:2278– 2287.
ID: 147467
Type: article
Authors: Hayward, Christopher C.; Chapman, Scott C.; Steidel, Charles C.; Golob, Anneya; Casey, Caitlin M.; Smith, Daniel J. B.; Zitrin, Adi; Blain, Andrew W.; Bremer, Malcolm N.; Chen, Chian-Chou; Coppin, Kristen E. K.; Farrah, Duncan; Ibar, Eduardo; Michalowski, Michal J.; Sawicki, Marcin; Scott, Douglas; van der Werf, Paul; Fazio, Giovanni G.; Geach, James E.; Gurwell, Mark; Petitpas, Glen; Wilner, David J.
Abstract: Interferometric observations have demonstrated that a significant fraction of single-dish submillimetre (submm) sources are blends of multiple submm galaxies (SMGs), but the nature of this multiplicity, i.e. whether the galaxies are physically associated or chance projections, has not been determined. We performed spectroscopy of 11 SMGs in six multicomponent submm sources, obtaining spectroscopic redshifts for nine of them. For an additional two component SMGs, we detected continuum emission but no obvious features. We supplement our observed sources with four single-dish submm sources from the literature. This sample allows us to statistically constrain the physical nature of single-dish submm source multiplicity for the first time. In three (3/7, { or} 43^{+39 }_{ -33} {per cent at 95 {per cent} confidence}) of the single-dish sources for which the nature of the blending is unambiguous, the components for which spectroscopic redshifts are available are physically associated, whereas 4/7 (57^{+33 }_{ -39} per cent) have at least one unassociated component. When components whose spectra exhibit continuum but no features and for which the photometric redshift is significantly different from the spectroscopic redshift of the other component are also considered, 6/9 (67^{+26 }_{ -37} per cent) of the single-dish sources are comprised of at least one unassociated component SMG. The nature of the multiplicity of one single-dish source is ambiguous. We conclude that physically associated systems and chance projections both contribute to the multicomponent single-dish submm source population. This result contradicts the conventional wisdom that bright submm sources are solely a result of merger-induced starbursts, as blending of unassociated galaxies is also important.
Submillimeter Array Observations of Extended CO (J = 2 ‑ 1) Emission in the Interacting Galaxy NGC 3627Law, Charles J.Zhang, QizhouRicci, LucaPetitpas, GlenJiménez-Donaire, Maria J.Ueda, JunkoLu, XingDunham, Michael M.DOI: info:10.3847/1538-4357/aadca9v. 86517
Law, Charles J., Zhang, Qizhou, Ricci, Luca, Petitpas, Glen, Jiménez-Donaire, Maria J., Ueda, Junko, Lu, Xing, and Dunham, Michael M. 2018. "Submillimeter Array Observations of Extended CO (J = 2 ‑ 1) Emission in the Interacting Galaxy NGC 3627." The Astrophysical Journal 865:17.
ID: 149162
Type: article
Authors: Law, Charles J.; Zhang, Qizhou; Ricci, Luca; Petitpas, Glen; Jiménez-Donaire, Maria J.; Ueda, Junko; Lu, Xing; Dunham, Michael M.
Abstract: We present moderate (∼5″) and high angular resolution (∼1″) observations of 12CO (J = 2 ‑ 1) emission toward the nearby interacting galaxy NGC 3627 taken with the Submillimeter Array (SMA). These SMA mosaic maps of NGC 3627 reveal a prominent nuclear peak, inter-arm regions, and diffuse, extended emission in the spiral arms. A velocity gradient of ∼400–450 km s‑1 is seen across the entire galaxy with velocity dispersions ranging from ≲80 km s‑1 toward the nuclear region to ≲15 km s‑1 in the spiral arms. We also detect unresolved 13CO (J = 2 ‑ 1) line emission toward the nuclear region, southern bar end, and in a relatively isolated clump in the southern portion of the galaxy, while no C18O(J = 2 ‑ 1) line emission is detected at a 3σ rms noise level of 42 mJy beam‑1 per 20 km s‑1 channel. Using RADEX modeling with a large velocity gradient approximation, we derive kinetic temperatures ranging from ∼5 to 10 K (in the spiral arms) to ∼25 K (at the center) and H2 number densities from ∼400 to 1000 cm‑3 (in the spiral arms) to ∼12,500 cm‑3 (at the center). From this density modeling, we find a total H2 mass of 9.6 × 109 M , which is ∼50% higher than previous estimates made using a constant H2–CO conversion factor, but is largely dependent on the assumed vertical distribution of the CO gas. With the exception of the nuclear region, we also identify a tentative correlation between star formation efficiency and kinetic temperature. We derive a galactic rotation curve, finding a peak velocity of ∼207 km s‑1 and estimate a total dynamical mass of 4.94 ± 0.70 × 1010 M at a galactocentric radius of ∼6.2 kpc (121″).
The effect of ram pressure on the molecular gas of galaxies: three case studies in the Virgo clusterLee, BumhyunChung, AereeTonnesen, StephanieKenney, Jeffrey D. P.Wong, O. IvyVollmer, B.Petitpas, Glen R.Crowl, Hugh H.van Gorkom, JacquelineDOI: info:10.1093/mnras/stw3162v. 4661382–1398
Lee, Bumhyun, Chung, Aeree, Tonnesen, Stephanie, Kenney, Jeffrey D. P., Wong, O. Ivy, Vollmer, B., Petitpas, Glen R., Crowl, Hugh H., and van Gorkom, Jacqueline. 2017. "The effect of ram pressure on the molecular gas of galaxies: three case studies in the Virgo cluster." Monthly Notices of the Royal Astronomical Society 466:1382– 1398.
ID: 143263
Type: article
Authors: Lee, Bumhyun; Chung, Aeree; Tonnesen, Stephanie; Kenney, Jeffrey D. P.; Wong, O. Ivy; Vollmer, B.; Petitpas, Glen R.; Crowl, Hugh H.; van Gorkom, Jacqueline
Abstract: We present 12CO (2-1) data of three Virgo spirals - NGC 4330, NGC 4402 and NGC 4522 obtained using the Submillimeter Array. These three galaxies show clear evidence of ram pressure stripping due to the cluster medium as found in previous H I imaging studies. Using the high-resolution CO data, we investigate how the properties of the inner molecular gas disc change while a galaxy is undergoing H I stripping in the cluster. At given sensitivity limits, we do not find any clear signs of molecular gas stripping. However, both its morphology and kinematics appear to be quite disturbed as those of H I. Morphological peculiarities present in the molecular and atomic gas are closely related with each other, suggesting that the molecular gas can be also affected by strong intracluster medium (ICM) pressure even if it is not stripped. CO is found to be modestly enhanced along the upstream sides in these galaxies, which may change the local star formation activity in the disc. Indeed, the distribution of H? emission, a tracer of recent star formation, well coincides with that of the molecular gas, revealing enhancements near the local CO peak or along the CO compression. FUV and H? share some properties in common, but FUV is always more extended than CO/H? in the three galaxies, implying that the star-forming disc is rapidly shrinking as the molecular gas properties have changed. We discuss how ICM pressure affects dense molecular gas and hence star formation properties while diffuse atomic gas is being removed from a galaxy.
Luminous Infrared Galaxies with the Submillimeter Array. V. Molecular Gas in Intermediate to Late-stage MergersSliwa, KazimierzWilson, Christine D.Matsushita, SatokiPeck, Alison B.Petitpas, Glen R.Saito, ToshikiYun, MinDOI: info:10.3847/1538-4357/aa689bv. 8408
Sliwa, Kazimierz, Wilson, Christine D., Matsushita, Satoki, Peck, Alison B., Petitpas, Glen R., Saito, Toshiki, and Yun, Min. 2017. "Luminous Infrared Galaxies with the Submillimeter Array. V. Molecular Gas in Intermediate to Late-stage Mergers." The Astrophysical Journal 840:8.
ID: 143330
Type: article
Authors: Sliwa, Kazimierz; Wilson, Christine D.; Matsushita, Satoki; Peck, Alison B.; Petitpas, Glen R.; Saito, Toshiki; Yun, Min
Abstract: We present new high-resolution ALMA (13CO J = 1-0 and J = 2-1) and CARMA (12CO and 13CO J = 1-0) observations of two luminous infrared galaxies (LIRGs), Arp 55 and NGC 2623. The new data are complementary to published and archival submillimeter array observations of 12CO J = 2-1 and J = 3-2. We perform a Bayesian likelihood non-local thermodynamic equilibrium analysis to constrain the molecular gas physical conditions such as temperature, column, and volume densities and the [12CO]/[13CO] abundance ratio. For Arp 55, an early/intermediate-staged merger, the line measurements are consistent with cold (~10-20 K), dense (>{10}3.5 cm-3) molecular gas. For NGC 2623, the molecular gas is warmer (~110 K) and less dense (~ {10}2.7 cm-3). Because Arp 55 is an early/intermediate stage merger, while NGC 2623 is a merger remnant, the difference in physical conditions may be an indicator of merger stage. Comparing the temperature and volume density of several LIRGs shows that the molecular gas, averaged over ~kiloparsec scales, of advanced mergers is in general warmer and less dense than early/intermediate stage mergers. We also find that the [12CO]/[13CO] abundance ratio of NGC 2623 is unusually high (>250) when compared with the Milky Way; however, it follows a trend seen with other LIRGs in the literature. This high [12CO]/[13CO] value is very likely due to stellar nucleosynthesis enrichment of the interstellar medium. On the other hand, Arp 55 has a more Galactic [12CO]/[13CO] value with the most probable [12CO]/[13CO] value being 20-30. We measure the CO-to-H2 conversion factor, {? }{CO}, to be ~0.1 and ~0.7 (3 × 10-4/{x}{CO}) M ? (K km s-1 pc2)-1 for Arp 55 and NGC 2623, respectively. Because Arp 55 is an early/intermediate-stage merger, this suggests that the transition from a Galactic conversion factor to a LIRG value happens at an even earlier merger stage.
Extreme jet ejections from the black hole X-ray binary V404 CygniTetarenko, A. J.Sivakoff, G. R.Miller-Jones, J. C. A.Rosolowsky, E. W.Petitpas, G.Gurwell, M.Wouterloot, J.Fender, R.Heinz, S.Maitra, D.Markoff, S. B.Migliari, S.Rupen, M. P.Rushton, A. P.Russell, D. M.Russell, T. D.Sarazin, C. L.DOI: info:10.1093/mnras/stx1048v. 4693141–3162
Tetarenko, A. J., Sivakoff, G. R., Miller-Jones, J. C. A., Rosolowsky, E. W., Petitpas, G., Gurwell, M., Wouterloot, J., Fender, R., Heinz, S., Maitra, D., Markoff, S. B., Migliari, S., Rupen, M. P., Rushton, A. P., Russell, D. M., Russell, T. D., and Sarazin, C. L. 2017. "Extreme jet ejections from the black hole X-ray binary V404 Cygni." Monthly Notices of the Royal Astronomical Society 469:3141– 3162.
ID: 143848
Type: article
Authors: Tetarenko, A. J.; Sivakoff, G. R.; Miller-Jones, J. C. A.; Rosolowsky, E. W.; Petitpas, G.; Gurwell, M.; Wouterloot, J.; Fender, R.; Heinz, S.; Maitra, D.; Markoff, S. B.; Migliari, S.; Rupen, M. P.; Rushton, A. P.; Russell, D. M.; Russell, T. D.; Sarazin, C. L.
Abstract: We present simultaneous radio through sub-mm observations of the black hole X-ray binary (BHXB) V404 Cygni during the most active phase of its June 2015 outburst. Our 4 h long set of overlapping observations with the Very Large Array, the Sub-millimeter Array and the James Clerk Maxwell Telescope (SCUBA-2) covers eight different frequency bands (including the first detection of a BHXB jet at 666 GHz/450 μm), providing an unprecedented multifrequency view of the extraordinary flaring activity seen during this period of the outburst. In particular, we detect multiple rapidly evolving flares, which reach Jy-level fluxes across all of our frequency bands. With this rich data set, we performed detailed MCMC modelling of the repeated flaring events. Our custom model adapts the van der Laan synchrotron bubble model to include twin bi-polar ejections, propagating away from the black hole at bulk relativistic velocities, along a jet axis that is inclined to the line of sight. The emission predicted by our model accounts for projection effects, relativistic beaming and the geometric time delay between the approaching and receding ejecta in each ejection event. We find that a total of eight bi-polar, discrete jet ejection events can reproduce the emission that we observe in all of our frequency bands remarkably well. With our best-fitting model, we provide detailed probes of jet speed, structure, energetics and geometry. Our analysis demonstrates the paramount importance of the mm/sub-mm bands, which offer a unique, more detailed view of the jet than can be provided by radio frequencies alone.
SMA Observations of the Extended 12CO(J = 6-5) Emission in the Starburst Galaxy NGC 253Krips, M.Martín, S.Peck, A. B.Sakamoto, K.Neri, R.Gurwell, M.Petitpas, Glen R.Zhao, Jun-HuiDOI: info:10.3847/0004-637X/821/2/112v. 821112
Krips, M., Martín, S., Peck, A. B., Sakamoto, K., Neri, R., Gurwell, M., Petitpas, Glen R., and Zhao, Jun-Hui. 2016. "SMA Observations of the Extended 12CO(J = 6-5) Emission in the Starburst Galaxy NGC 253." The Astrophysical Journal 821:112.
ID: 139620
Type: article
Authors: Krips, M.; Martín, S.; Peck, A. B.; Sakamoto, K.; Neri, R.; Gurwell, M.; Petitpas, Glen R.; Zhao, Jun-Hui
Abstract: We present observations of the 12CO(J = 6-5) line and 686 GHz continuum emission in NGC 253 with the Submillimeter Array at an angular resolution of ~4´´. The 12CO(J = 6-5) emission is clearly detected along the disk and follows the distribution of the lower 12CO line transitions with little variation of the line ratios. A large velocity gradient analysis suggests a two-temperature model of the molecular gas in the disk, likely dominated by a combination of low-velocity shocks and the disk-wide photodissociation regions. Only marginal 12CO(J = 6-5) emission is detected in the vicinity of the expanding shells at the eastern and western edges of the disk. While the eastern shell contains gas even warmer (Tkin > 300 K) than the hot gas component (Tkin = 300 K) of the disk, the western shell is surrounded by gas much cooler (Tkin = 60 K) than the eastern shell but somewhat hotter than the cold gas component of the disk (for similar H2 and CO column densities), indicative of different (or differently efficient) heating mechansisms. The continuum emission at 686 GHz in the disk agrees well in shape and size with that at lower (sub)millimeter frequencies, exhibiting a spectral index consistent with thermal dust emission. We find dust temperatures of ~10-30 K and largely optically thin emission. However, our fits suggest a second (more optically thick) dust component at higher temperatures ({T}{{d}}\gt 60 K), similar to the molecular gas. We estimate a global dust mass of ~106 {M}? for the disk, translating into a gas-to-dust mass ratio of a few hundred, consistent with other nearby active galaxies.
Constraints on the circumstellar dust around KIC 8462852Thompson, M. A.Scicluna, P.Kemper, F.Geach, J. E.Dunham, M. M.Morata, O.Ertel, S.Ho, P. T. P.Dempsey, J.Coulson, I.Petitpas, Glen R.Kristensen, L. E.DOI: info:10.1093/mnrasl/slw008v. 458L39–L43
Thompson, M. A., Scicluna, P., Kemper, F., Geach, J. E., Dunham, M. M., Morata, O., Ertel, S., Ho, P. T. P., Dempsey, J., Coulson, I., Petitpas, Glen R., and Kristensen, L. E. 2016. "Constraints on the circumstellar dust around KIC 8462852." Monthly Notices of the Royal Astronomical Society 458:L39– L43.
ID: 139781
Type: article
Authors: Thompson, M. A.; Scicluna, P.; Kemper, F.; Geach, J. E.; Dunham, M. M.; Morata, O.; Ertel, S.; Ho, P. T. P.; Dempsey, J.; Coulson, I.; Petitpas, Glen R.; Kristensen, L. E.
Abstract: We present millimetre (Submillimeter Array) and submillimetre (SCUBA-2) continuum observations of the peculiar star KIC 8462852 which displayed several deep and aperiodic dips in brightness during the Kepler mission. Our observations are approximately confusion-limited at 850 ?m and are the deepest millimetre and submillimetre photometry of the star that has yet been carried out. No significant emission is detected towards KIC 8462852. We determine upper limits for dust between a few 10-6 M? and 10-3 M? for regions identified as the most likely to host occluding dust clumps and a total overall dust budget of for regions identified as the most likely to host occluding dust clumps and a total overall dust budget of ? within a radius of 200 au. Such low limits for the inner system make the catastrophic planetary disruption hypothesis unlikely. Integrating over the Kepler light curve we determine that at least 10-9 M? of dust is required to cause the observed Q16 dip. This is consistent with the currently most favoured cometary breakup hypothesis, but nevertheless implies the complete breakup of ~30 Comet 1/P Halley type objects. Finally, in the wide SCUBA-2 field of view we identify another candidate debris disc system that is potentially the largest yet discovered.
Planck's dusty GEMS: The brightest gravitationally lensed galaxies discovered with the Planck all-sky surveyCañameras, R.Nesvadba, N. P. H.Guery, D.McKenzie, T.König, S.Petitpas, Glen R.Dole, H.Frye, B.Flores-Cacho, I.Montier, L.Negrello, M.Beelen, A.Boone, F.Dicken, D.Lagache, G.Le Floc'h, E.Altieri, B.Béthermin, M.Chary, Zotti, G.Giard, M.Kneissl, R.Krips, M.Malhotra, S.Martinache, C.Omont, A.Pointecouteau, E.Puget, J. -LScott, D.Soucail, G.Valtchanov, I.Welikala, N.Yan, L.DOI: info:10.1051/0004-6361/201425128v. 581A105
Cañameras, R., Nesvadba, N. P. H., Guery, D., McKenzie, T., König, S., Petitpas, Glen R., Dole, H., Frye, B., Flores-Cacho, I., Montier, L., Negrello, M., Beelen, A., Boone, F., Dicken, D., Lagache, G., Le Floc'h, E., Altieri, B., Béthermin, M., Chary, R., de Zotti, G., Giard, M., Kneissl, R., Krips, M., Malhotra, S., Martinache, C. et al. 2015. "Planck's dusty GEMS: The brightest gravitationally lensed galaxies discovered with the Planck all-sky survey." Astronomy and Astrophysics 581:A105.
ID: 140502
Type: article
Authors: Cañameras, R.; Nesvadba, N. P. H.; Guery, D.; McKenzie, T.; König, S.; Petitpas, Glen R.; Dole, H.; Frye, B.; Flores-Cacho, I.; Montier, L.; Negrello, M.; Beelen, A.; Boone, F.; Dicken, D.; Lagache, G.; Le Floc'h, E.; Altieri, B.; Béthermin, M.; Chary, R.; de Zotti, G.; Giard, M.; Kneissl, R.; Krips, M.; Malhotra, S.; Martinache, C.; Omont, A.; Pointecouteau, E.; Puget, J. -L; Scott, D.; Soucail, G.; Valtchanov, I.; Welikala, N.; Yan, L.
Abstract: We present an analysis of CO spectroscopy and infrared-to-millimetre dust photometry of 11 exceptionally bright far-infrared (FIR) and sub-mm sources discovered through a combination of the Planck all-sky survey and follow-up Herschel-SPIRE imaging - "Planck's Dusty Gravitationally Enhanced subMillimetre Sources". Each source has a secure spectroscopic redshift z = 2.2-3.6 from multiple lines obtained through a blind redshift search with EMIR at the IRAM 30-m telescope. Interferometry was obtained at IRAM and the SMA, and along with optical/near-infrared imaging obtained at the CFHT and the VLT reveal morphologies consistent with strongly gravitationally lensed sources, including several giant arcs. Additional photometry was obtained with JCMT/SCUBA-2 and IRAM/GISMO at 850 ?m and 2 mm, respectively. The SEDs of our sources peak near either the 350 ?m or 500 ?m bands of SPIRE with peak flux densities between 0.35 and 1.14 Jy. All objects are extremely bright isolated point sources in the 18'' beam of SPIREat 250 ?m, with apparent FIR luminosities of up to 3 × 1014 L? (not correcting for the lensing effect). Their morphologies, sizes, CO line widths, CO luminosities, dust temperatures, and FIR luminosities provide additional empirical evidence that these are amongst the brightest strongly gravitationally lensed high-redshift galaxies on the sub-mm sky. Our programme extends the successful wide-area searches for strongly gravitationally lensed high-redshift galaxies (carried out with the South Pole Telescope and Herschel) towards even brighter sources, which are so rare that their systematic identification requires a genuine all-sky survey like Planck. Six sources are above the ?600 mJy 90% completeness limit of the Planck catalogue of compact sources (PCCS) at 545 and 857 GHz, which implies that these must literally be amongst the brightest high-redshift FIR and sub-mm sources on the extragalactic sky. We discuss their dust masses and temperatures, and use additional WISE 22-?m photometry and template fitting to rule out a significant contribution of AGN heating to the total infrared luminosity. Six sources are detected in FIRST at 1.4 GHz, and the others have sensitive upper limits. Four have flux densities brighter than expected from the local FIR-radio correlation, but in the range previously found for high-z sub-mm galaxies, one has a deficit of FIR emission, and 6 are consistent with the local correlation, although this includes 3 galaxies with upper limits. We attribute this to the turbulent interstellar medium of these galaxies, rather than the presence of radio AGN. The global dust-to-gas ratios and star-formation efficiencies of our sources are predominantly in the range expected from massive, metal-rich, intense, high-redshift starbursts. An extensive multi-wavelength follow-up programme is being carried out to further characterize these sources and the intense star formation within them. Based on observations collected with the Herschel and Planck satellites, IRAM, SMA, JCMT, CFHT, and the VLT.
A millimetre-wave redshift search for the unlensed HyLIRG, HS1700.850.1Chapman, S. C.Bertoldi, F.Smail, IanSteidel, C. C.Blain, A. W.Geach, J. E.Gurwell, M.Ivison, R. J.Petitpas, Glen R.Reddy, N.DOI: info:10.1093/mnras/stv1618v. 453951–959
Chapman, S. C., Bertoldi, F., Smail, Ian, Steidel, C. C., Blain, A. W., Geach, J. E., Gurwell, M., Ivison, R. J., Petitpas, Glen R., and Reddy, N. 2015. "A millimetre-wave redshift search for the unlensed HyLIRG, HS1700.850.1." Monthly Notices of the Royal Astronomical Society 453:951– 959.
ID: 140564
Type: article
Authors: Chapman, S. C.; Bertoldi, F.; Smail, Ian; Steidel, C. C.; Blain, A. W.; Geach, J. E.; Gurwell, M.; Ivison, R. J.; Petitpas, Glen R.; Reddy, N.
Abstract: We report the redshift of an unlensed, highly obscured submillimetre galaxy (SMG), HS1700.850.1, the brightest SMG (S850 ?m = 19.1 mJy) detected in the James Clerk Maxwell Telescope/Submillimetre Common-user Bolometer Array-2 (JCMT/SCUBA-2) Baryonic Structure Survey, based on the detection of its 12CO line emission. Using the Institute Radio Astronomie Millimetrique Plateau de Bure Interferometer with 3.6 GHz band width, we serendipitously detect an emission line at 150.6 GHz. From a search over 14.5 GHz in the 3- and 2-mm atmospheric windows, we confirm the identification of this line as 12CO(5-4) at z = 2.816, meaning that it does not reside in the z ~ 2.30 proto-cluster in this field. Measurement of the 870 ?m source size (CO(5-4) at z = 2.816, meaning that it does not reside in the z ~ 2.30 proto-cluster in this field. Measurement of the 870 ?m source size (870 ?m = 14.5 mJy, LIR ~ 1013 L? component, suggesting an Eddington-limited starburst. We use the double-peaked 12CO line profile measurements along with the SMA size constraints to study the gas dynamics of a HyLIRG, estimating the gas and dynamical masses of HS1700.850.1. While HS1700.850.1 is one of the most extreme galaxies known in the Universe, we find that it occupies a relative void in the Lyman-Break Galaxy distribution in this field. Comparison with other extreme objects at similar epochs (HyLIRG Quasars), and cosmological simulations, suggests such an anti-bias of bright SMGs could be relatively common, with the brightest SMGs rarely occupying the most overdense regions at z = 2-4.
High-resolution Observations of Molecular Gas in the Early-type Dwarf Galaxy NGC 404Taylor, Christopher L.Petitpas, Glen R.del Rio, M. S.DOI: info:10.1088/0004-6256/149/6/187v. 149187
Taylor, Christopher L., Petitpas, Glen R., and del Rio, M. S. 2015. "High-resolution Observations of Molecular Gas in the Early-type Dwarf Galaxy NGC 404." The Astronomical Journal 149:187.
ID: 136602
Type: article
Authors: Taylor, Christopher L.; Petitpas, Glen R.; del Rio, M. S.
Abstract: We present Berkeley-Illinois-Maryland Association CO (1-0) observations of the nearby dwarf elliptical galaxy NGC 404. The detected CO emission is concentrated in a small feature, slightly larger than the beam size, at the center of the optical galaxy. For an assumed CO-to-H2 conversion factor of 2.3 × {{10}20} (K km s-1)-1, the molecular gas mass is 9.0 × {{10}6} M?. The velocity field suggests rotation, with a position angle ~90° different from previous single-dish observations. Both position angles are different from that of the extended H i distribution detected by del Rió et al. The lack of agreement between the postion angle of the