%0 Generic %1 liang2014mining %A Liang, Cameron Jia %A Chen, Hsiao-Wen %D 2014 %K cgm dwarf low-z metals %T Mining Circumgalactic Baryons in the Low-Redshift Universe %U http://arxiv.org/abs/1402.3602 %X (Abridged) This paper presents an absorption-line study of the multiphase circumgalactic medium (CGM) based on observations of a suite of absorption features including Lya, CII, CIV, SiII, SiIII, and SiIV transitions. Cross-matching between public galaxy and QSO survey data has yielded 111 independent galaxy and QSO pairs for which high-quality archival UV spectra of the QSOs and multi-wavelength observations of the galaxies are available. The galaxy sample is characterized by a median redshift of <z> = 0.0232, a median projected distance of <d> = 342 kpc, and a median stellar mass of log (Mstar/Msun) = 9.040.93. It is therefore dominated by low-mass dwarf galaxies. Comparing the absorber features identified in the QSO spectra with galaxy properties has led to strong constraints for the CGM at z<~0.06. While abundant hydrogen gas is found beyond the dark matter halo radius Rh and all through d~500 kpc with a mean covering fraction of ~50%, no heavy elements are detected at d>~0.5 Rh. The lack of heavy elements at large distances is unlikely due to ionization effects, since it persists through all ionization states included in the study. Considering all galaxies at d>Rh leads to a strict upper limit for the covering fraction of heavy elements of ~4% (at a 95% confidence level) over d=(1-10) Rh. At d<0.5 Rh, differential covering fraction between low- and high-ionization gas is observed, suggesting that the CGM becomes progressively more ionized from d<0.2 Rh to larger distances. Comparing absorption-line observations of the CGM at low and high redshifts shows that massive starburst galaxies at z=2.2 exhibit significantly stronger mean absorption than dwarf galaxies at z~0 and the distinction is most pronounced in low-ionization species traced by CII and SiII absorption lines, suggesting distinct ionization conditions between the CGM at low and high redshifts.

@misc{liang2014mining, abstract = {(Abridged) This paper presents an absorption-line study of the multiphase circumgalactic medium (CGM) based on observations of a suite of absorption features including Lya, CII, CIV, SiII, SiIII, and SiIV transitions. Cross-matching between public galaxy and QSO survey data has yielded 111 independent galaxy and QSO pairs for which high-quality archival UV spectra of the QSOs and multi-wavelength observations of the galaxies are available. The galaxy sample is characterized by a median redshift of <z> = 0.0232, a median projected distance of <d> = 342 kpc, and a median stellar mass of log (Mstar/Msun) = 9.04\pm 0.93. It is therefore dominated by low-mass dwarf galaxies. Comparing the absorber features identified in the QSO spectra with galaxy properties has led to strong constraints for the CGM at z<~0.06. While abundant hydrogen gas is found beyond the dark matter halo radius Rh and all through d~500 kpc with a mean covering fraction of ~50%, no heavy elements are detected at d>~0.5 Rh. The lack of heavy elements at large distances is unlikely due to ionization effects, since it persists through all ionization states included in the study. Considering all galaxies at d>Rh leads to a strict upper limit for the covering fraction of heavy elements of ~4% (at a 95% confidence level) over d=(1-10) Rh. At d<0.5 Rh, differential covering fraction between low- and high-ionization gas is observed, suggesting that the CGM becomes progressively more ionized from d<0.2 Rh to larger distances. Comparing absorption-line observations of the CGM at low and high redshifts shows that massive starburst galaxies at z=2.2 exhibit significantly stronger mean absorption than dwarf galaxies at z~0 and the distinction is most pronounced in low-ionization species traced by CII and SiII absorption lines, suggesting distinct ionization conditions between the CGM at low and high redshifts.}, added-at = {2014-02-18T10:31:03.000+0100}, author = {Liang, Cameron Jia and Chen, Hsiao-Wen}, biburl = {https://www.bibsonomy.org/bibtex/2a47d22dcfb497dc83a980b386286aed4/miki}, description = {[1402.3602] Mining Circumgalactic Baryons in the Low-Redshift Universe}, interhash = {7e7803cfced1a1f041854e85b047cd31}, intrahash = {a47d22dcfb497dc83a980b386286aed4}, keywords = {cgm dwarf low-z metals}, note = {cite arxiv:1402.3602Comment: 27 pages, 10 figures, submitted to MNRAS}, timestamp = {2014-02-18T10:31:03.000+0100}, title = {Mining Circumgalactic Baryons in the Low-Redshift Universe}, url = {http://arxiv.org/abs/1402.3602}, year = 2014 }