GMRT mini-survey to search for 21-cm absorption in Quasar-Galaxy Pairs at z~0.1

Abstract

We present the results from our 21-cm absorption survey of a sample of 5 quasar-galaxy pairs (QGPs), with the redshift of the galaxies in the range 0.03<zg<0.18, selected from the SDSS. The HI 21-cm absorption was searched towards the 9 sight lines with impact parameters ranging from 10 to 55 kpc using GMRT. 21-cm absorption was detected only in one case i.e. towards the Quasar (zq=2.625 SDSS J124157.54+633241.6)-galaxy (zg=0.143 SDSS J124157.26+633237.6) pair with the impact parameter 11 kpc. The quasar sight line in this case pierces through the stellar disk of a galaxy having near solar metallicity (i.e (O/H)+12=8.7) and star formation rate uncorrected for dust attenuation of 0.1 M_odot/yr. The quasar spectrum reddened by the foreground galaxy is well fitted with the Milky Way extinction curve (with an Av of 0.44) and the estimated HI column density is similar to the value obtained from 21-cm absorption assuming spin temperature of 100K. Combining our sample with the z<0.1 data available in the literature, we find the detectability of 21-cm absorption with integrated optical depth greater than 0.1 km\s to be 50% for the impact parameter less than 20 kpc. Using the surface brightness profiles and relationship between the optical size and extent of the HI disk known for nearby galaxies, we conclude that in most of the cases of 21-cm absorption non-detection, the sight lines may not be passing through the HI gas. We also find that in comparison to the absorption systems associated with these QGPs, z<1 DLAs with 21-cm absorption detections have lower CaII equivalent widths despite having higher 21-cm optical depths and smaller impact parameters. This suggests that the current sample of DLAs may be a biased population that avoids sight lines through dusty star-forming galaxies. A systematic survey of QGPs is needed to confirm these findings and understand the nature of 21-cm absorbers.

17 pages, 5 tables, 19 figures, accepted for publication in MNRAS (abstract abridged)

References in corpus (15)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• High-Resolution Rotation Curves and Galaxy Mass Models from THINGS
• The cold gaseous halo of NGC 891
• Halo Gas Cross Sections And Covering Fractions of MgII Absorption Selected Galaxies
• WSRT Ultra-Deep Neutral Hydrogen Imaging of Galaxy Clusters at z=0.2, a Pilot Survey of Abell 963 and Abell 2192
• A Pilot Survey of HI in Field Galaxies at Redshift z~0.2
• Detection of the 2175Å~ extinction feature and 21-cm absorption in two MgII systems at z~1.3
• Aperture Synthesis Observations of the Nearby Spiral NGC 6503: Modeling the Thin and Thick HI Disks
• The star formation rate of CaII and damped Lyman-alpha absorbers at 0.4<z<1.3
• Measurements of CaII absorption, metals, and dust in a sample of z~1 DLAs and subDLAs
• The detectability of HI 21-cm absorption in damped Lyman-alpha systems
• The host galaxies of strong CaII QSO absorption systems at z<0.5
• Detection of broad 21-cm absorption at z = 0.656 in the complex sight-line towards 3C336
• Dust depletion, chemical uniformity and environment of CaII H&K quasar absorbers
• Detecting cold gas at intermediate redshifts: GMRT survey using Mg II systems

Cited by in corpus (33)

• Multiphase Gas In Galaxy Halos: The OVI Lyman-limit System toward J1009+0713
• Search for cold gas in strong MgII absorbers at 0.5<z<1.5: nature and evolution of 21-cm absorbers
• Parsec-scale structures and diffuse bands in a translucent interstellar medium at z 0.079
• The First Large Absorption Survey in HI (FLASH): I. Science Goals and Survey Design
• 21-cm absorption from galaxies at z ~ 0.3
• Blind HI and OH absorption line search: first results with MALS and uGMRT processed using ARTIP
• Application of a Bayesian Method to Absorption Spectral-Line Finding in Simulated ASKAP Data
• Urchin: A Reverse Ray Tracer for Astrophysical Applications
• HI 21-cm absorption survey of quasar-galaxy pairs: Distribution of cold gas around z<0.4 galaxies
• HI emission and absorption in nearby, gas-rich galaxies II. -- sample completion and detection of intervening absorption in NGC 5156
• New HI 21-cm absorbers at low and intermediate redshifts
• A GBT Survey for HI 21 cm Absorption in the Disks and Halos of Low-Redshift Galaxies
• A correlation between the HI 21-cm absorption strength and impact parameter in external galaxies
• Revealing HI gas in emission and absorption on pc to kpc scales in a galaxy at z ~ 0.017
• Circumnuclear and infalling HI gas in a merging galaxy pair at z=0.123
• HI emission and absorption in nearby, gas-rich galaxies
• Mapping kiloparsec-scale structures in the extended HI disc of the galaxy UGC 00439 by HI 21-cm absorption
• Incidence of HI 21-cm absorption in strong FeII systems at $0.5<z<1.5$
• Galaxies with Background QSOs, I: A Search for Strong Galactic H-alpha Lines
• Discovery of OH absorption from a galaxy at z~0.05: implications for large surveys with SKA pathfinders
• Damped Ly-alpha Absorbers in Star-forming Galaxies at z < 0.15 Detected with the Hubble Space Telescope and Implications for Galaxy Evolution
• Small-scale Properties of Atomic Gas in Extended Disks of Galaxies
• Galactic nebular lines in the fiber spectra of background QSOs: Reaching a hundred QSO-galaxy pairs with spectroscopic and photometric measurements
• Evolution of cold gas at 2<z<5: a blind search for HI and OH absorption lines towards mid-infrared color selected radio-loud AGNs
• Distribution of Cold ($\lesssim 300$K) Atomic Gas in Galaxies: Results from the GBT HI Absorption Survey Probing the Inner Halos ($\rho <20$kpc) of Low-z Galaxies
• HI 21-cm absorption from $z\sim 0.35$ strong MgII absorbers
• Nature of the Galaxies On Top Of Quasars producing MgII absorption
• Probing galaxy evolution through HI 21-cm emission and absorption: current status and prospects with the Square Kilometre Array
• Cold neutral hydrogen gas in galaxies
• Disc galaxy resolved in HI absorption against the radio lobe of 3C 433: Case study for future surveys
• On the scarcity of redshifted OH and millimetre-band molecular absorption
• High spin temperatures at large impact parameters: Ionisation in the outskirts of galaxies
• HI 21-cm Absorption Associated with Foreground Galaxies on Top of Quasars