Using VLT/X-shooter we searched for emission line galaxies associated to four
damped Lyman-$\alpha$ systems (DLAs) and one sub-DLA at 2.73<=z<=3.25 towards
QSO J2358+0149. We detect O III emission from a "low-cool" DLA at z_abs =
2.9791 (having log N(HI)=21.69+\-0.10, Zn/H = -1.83+\-0.18) at an impact
parameter of, $\rho$ ~12 kpc. The associated galaxy is compact with a dynamical
mass of (1-6)x10^9 M_solar, very high excitation (O III/O II and O
III/H$\beta$ both greater than 10), 12+O/H<=8.5 and moderate star
formation rate (SFR <=2 M_solar yr^-1). Such properties are typically seen in
the low-z extreme blue compact dwarf galaxies. The kinematics of the gas is
inconsistent with that of an extended disk and the gas is part of either a
large scale wind or cold accretion. We detect Ly$\alpha$ emission from the
z_abs = 3.2477 DLA (having log N(HI)=21.12+\-0.10 and Zn/H=-0.97+\-0.13).The
Ly$\alpha$ emission is redshifted with respect to the metal absorption lines by
320 km s^-1, consistent with the location of the red hump expected in
radiative transport models. We derive SFR ~0.2-1.7 M_solar yr^-1 and
Ly$\alpha$ escape fraction of >=10 per cent. No other emission line is detected
from this system. Because the DLA has a small velocity separation from the
quasar (~500 km s^-1) and the DLA emission is located within a small
projected distance ($\rho<5$ kpc), we also explore the possibility that the
Ly$\alpha$ emission is being induced by the QSO itself. QSO induced Ly$\alpha$
fluorescence is possible if the DLA is within a physical separation of 340 kpc
to the QSO. Detection of stellar continuum light and/or the oxygen emission
lines would disfavor this possibility. We do not detect any emission line from
the remaining three systems.
Description
[1604.06475] Detection of emission lines from z ~ 3 DLAs towards the QSO J2358+0149
%0 Generic
%1 srianand2016detection
%A Srianand, Raghunathan
%A Hussain, Tanvir
%A Noterdaeme, Pasquier
%A Petitjean, Patrick
%A Krühler, Thomas
%A Japelj, Jure
%A Pâris, Isabelle
%A Kashikawa, Nobunari
%D 2016
%K dla emission galaxies host
%T Detection of emission lines from z ~ 3 DLAs towards the QSO J2358+0149
%U http://arxiv.org/abs/1604.06475
%X Using VLT/X-shooter we searched for emission line galaxies associated to four
damped Lyman-$\alpha$ systems (DLAs) and one sub-DLA at 2.73<=z<=3.25 towards
QSO J2358+0149. We detect O III emission from a "low-cool" DLA at z_abs =
2.9791 (having log N(HI)=21.69+\-0.10, Zn/H = -1.83+\-0.18) at an impact
parameter of, $\rho$ ~12 kpc. The associated galaxy is compact with a dynamical
mass of (1-6)x10^9 M_solar, very high excitation (O III/O II and O
III/H$\beta$ both greater than 10), 12+O/H<=8.5 and moderate star
formation rate (SFR <=2 M_solar yr^-1). Such properties are typically seen in
the low-z extreme blue compact dwarf galaxies. The kinematics of the gas is
inconsistent with that of an extended disk and the gas is part of either a
large scale wind or cold accretion. We detect Ly$\alpha$ emission from the
z_abs = 3.2477 DLA (having log N(HI)=21.12+\-0.10 and Zn/H=-0.97+\-0.13).The
Ly$\alpha$ emission is redshifted with respect to the metal absorption lines by
320 km s^-1, consistent with the location of the red hump expected in
radiative transport models. We derive SFR ~0.2-1.7 M_solar yr^-1 and
Ly$\alpha$ escape fraction of >=10 per cent. No other emission line is detected
from this system. Because the DLA has a small velocity separation from the
quasar (~500 km s^-1) and the DLA emission is located within a small
projected distance ($\rho<5$ kpc), we also explore the possibility that the
Ly$\alpha$ emission is being induced by the QSO itself. QSO induced Ly$\alpha$
fluorescence is possible if the DLA is within a physical separation of 340 kpc
to the QSO. Detection of stellar continuum light and/or the oxygen emission
lines would disfavor this possibility. We do not detect any emission line from
the remaining three systems.
@misc{srianand2016detection,
abstract = {Using VLT/X-shooter we searched for emission line galaxies associated to four
damped Lyman-$\alpha$ systems (DLAs) and one sub-DLA at 2.73<=z<=3.25 towards
QSO J2358+0149. We detect [O III] emission from a "low-cool" DLA at z_abs =
2.9791 (having log N(HI)=21.69+\-0.10, [Zn/H] = -1.83+\-0.18) at an impact
parameter of, $\rho$ ~12 kpc. The associated galaxy is compact with a dynamical
mass of (1-6)x10^9 M_solar, very high excitation ([O III]/[O II] and [O
III]/[H$\beta$] both greater than 10), 12+[O/H]<=8.5 and moderate star
formation rate (SFR <=2 M_solar yr^{-1}). Such properties are typically seen in
the low-z extreme blue compact dwarf galaxies. The kinematics of the gas is
inconsistent with that of an extended disk and the gas is part of either a
large scale wind or cold accretion. We detect Ly$\alpha$ emission from the
z_abs = 3.2477 DLA (having log N(HI)=21.12+\-0.10 and [Zn/H]=-0.97+\-0.13).The
Ly$\alpha$ emission is redshifted with respect to the metal absorption lines by
320 km s^{-1}, consistent with the location of the red hump expected in
radiative transport models. We derive SFR ~0.2-1.7 M_solar yr^{-1} and
Ly$\alpha$ escape fraction of >=10 per cent. No other emission line is detected
from this system. Because the DLA has a small velocity separation from the
quasar (~500 km s^{-1}) and the DLA emission is located within a small
projected distance ($\rho<5$ kpc), we also explore the possibility that the
Ly$\alpha$ emission is being induced by the QSO itself. QSO induced Ly$\alpha$
fluorescence is possible if the DLA is within a physical separation of 340 kpc
to the QSO. Detection of stellar continuum light and/or the oxygen emission
lines would disfavor this possibility. We do not detect any emission line from
the remaining three systems.},
added-at = {2016-04-25T09:59:49.000+0200},
author = {Srianand, Raghunathan and Hussain, Tanvir and Noterdaeme, Pasquier and Petitjean, Patrick and Krühler, Thomas and Japelj, Jure and Pâris, Isabelle and Kashikawa, Nobunari},
biburl = {https://www.bibsonomy.org/bibtex/2be6427661e421a0319419d89ff06aec1/miki},
description = {[1604.06475] Detection of emission lines from z ~ 3 DLAs towards the QSO J2358+0149},
interhash = {c07954055d57121bac3982eed5a3aee7},
intrahash = {be6427661e421a0319419d89ff06aec1},
keywords = {dla emission galaxies host},
note = {cite arxiv:1604.06475Comment: 13 pages, 7 figures, 4 tables (3 pages, 5 figures, 5 tables in Appendix). Accepted for publication in MNRAS},
timestamp = {2016-04-25T09:59:49.000+0200},
title = {Detection of emission lines from z ~ 3 DLAs towards the QSO J2358+0149},
url = {http://arxiv.org/abs/1604.06475},
year = 2016
}