TY - JOUR
T1 - Disentangling the multiphase circumgalactic medium shared between a dwarf and a massive star-forming galaxy at z∼0.4
AU - Nateghi, Hasti
AU - Kacprzak, Glenn G.
AU - Nielsen, Nikole M.
AU - Muzahid, Sowgat
AU - Churchill, Christopher W.
AU - Pointon, Stephanie K.
AU - Charlton, Jane C.
N1 - Funding Information:
We thank the referee for their helpful comments that improved the manuscript. GGK and NMN acknowledge the support of the Australian Research Council through Discovery Project grant DP170103470. Parts of this research were supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. CWC and JCC were supported by the National Science Foundation through Collaborative Research grant AST-151786 and by NASA through HST grant GO-13398 from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. SM is supported by the Alexander von Humboldt Foundation (Germany) through the Experienced Researchers Fellowship. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. KCWI and ESI observations were supported by Swinburne Keck programs 2017B W270, 2018A W185, 2018B W232 (KCWI), and 2014A W178E (ESI). The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
PY - 2021/1/1
Y1 - 2021/1/1
N2 - Themultiphase circumgalactic medium (CGM) arises within the complex environment around a galaxy, or collection of galaxies, and possibly originates from a wide range of physical mechanisms. In this paper, we attempt to disentangle the origins of these multiphase structures and present a detailed analysis of the quasar field Q0122-003 field using Keck/KCWI galaxy observations and HST/COS spectra probing the CGM. Our re-analysis of this field shows that there are two galaxies associated with the absorption. We have discovered a dwarf galaxy, G 27kpc (M = 108.7M⊙), at z = 0.39863 that is 27 kpc from the quasar sightline. G 27kpc is only +21 km s-1 from a more massive (M = 1010.5M⊙) star-forming galaxy, G 163kpc, at an impact parameter of 163 kpc. While G 163kpc is actively forming stars (SFR = 6.9M⊙ yr-1), G 27kpc has a low star-formation rate (SFR = 0.08 ± 0.03M⊙ yr-1) and star formation surface density (ΣSFR = 0.006M⊙ kpc-2 yr-1), implying no active outflows. By comparing galaxy SFRs, kinematics, masses, and distances from the quasar sightline to the absorption kinematics, column densities, and metallicities, we have inferred the following: (1) Part of the low-ionization phase has a metallicity and kinematics consistent with being accreted on to G 27kpc. (2) The remainder of the low ionization phase has metallicities and kinematics consistent with being intragroup gas being transferred fromG 27kpc toG 163kpc. (3) The high ionization phase is consistent with being produced solely by outflows originating from the massive halo of G 163kpc. Our results demonstrate the complex nature of the multiphase CGM, especially around galaxy groups, and that detailed case-by-case studies are critical for disentangling its origins.
AB - Themultiphase circumgalactic medium (CGM) arises within the complex environment around a galaxy, or collection of galaxies, and possibly originates from a wide range of physical mechanisms. In this paper, we attempt to disentangle the origins of these multiphase structures and present a detailed analysis of the quasar field Q0122-003 field using Keck/KCWI galaxy observations and HST/COS spectra probing the CGM. Our re-analysis of this field shows that there are two galaxies associated with the absorption. We have discovered a dwarf galaxy, G 27kpc (M = 108.7M⊙), at z = 0.39863 that is 27 kpc from the quasar sightline. G 27kpc is only +21 km s-1 from a more massive (M = 1010.5M⊙) star-forming galaxy, G 163kpc, at an impact parameter of 163 kpc. While G 163kpc is actively forming stars (SFR = 6.9M⊙ yr-1), G 27kpc has a low star-formation rate (SFR = 0.08 ± 0.03M⊙ yr-1) and star formation surface density (ΣSFR = 0.006M⊙ kpc-2 yr-1), implying no active outflows. By comparing galaxy SFRs, kinematics, masses, and distances from the quasar sightline to the absorption kinematics, column densities, and metallicities, we have inferred the following: (1) Part of the low-ionization phase has a metallicity and kinematics consistent with being accreted on to G 27kpc. (2) The remainder of the low ionization phase has metallicities and kinematics consistent with being intragroup gas being transferred fromG 27kpc toG 163kpc. (3) The high ionization phase is consistent with being produced solely by outflows originating from the massive halo of G 163kpc. Our results demonstrate the complex nature of the multiphase CGM, especially around galaxy groups, and that detailed case-by-case studies are critical for disentangling its origins.
UR - http://www.scopus.com/inward/record.url?scp=85098555357&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85098555357&partnerID=8YFLogxK
U2 - 10.1093/mnras/staa3534
DO - 10.1093/mnras/staa3534
M3 - Article
AN - SCOPUS:85098555357
VL - 500
SP - 3987
EP - 3998
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 3
ER -