J/ApJ/920/95 MOSDEF-LRIS Survey: Star-forming galaxies properties (Du+, 2021)
The MOSDEF-LRIS Survey: Probing the ISM/CGM Structure of Star-forming Galaxies
at z∼2 Using Rest-UV Spectroscopy.
Du X., Shapley A.E., Topping M.W., Reddy N.A., Sanders R.L., Coil A.L.,
Kriek M.,Mobasher B.,Siana B.
<Astrophys. J., 920, 95 (2021)>
=2021ApJ...920...95D 2021ApJ...920...95D
ADC_Keywords: Galaxies; Star Forming Region; Interstellar medium;
Spectra, ultraviolet; Redshifts; Colors
Keywords: Interstellar medium ; Galaxy spectroscopy ; High-redshift
galaxies ; Circumgalactic medium ; Extragalactic astronomy
Abstract:
The complex structure of gas, metals, and dust in the interstellar and
circumgalactic medium (ISM and CGM, respectively) in star-forming
galaxies can be probed by Lyα emission and absorption,
low-ionization interstellar (LIS) metal absorption, and dust reddening
E(B-V). We present a statistical analysis of the mutual correlations
among Lyα equivalent width (EWLyα), LIS equivalent width
(EWLIS), and E(B-V) in a sample of 157 star-forming galaxies at z∼2.3.
With measurements obtained from individual deep rest-UV spectra and
spectral energy distribution modeling, we find that the tightest
correlation exists between EWLIS and E(B-V), although correlations
among all three parameters are statistically significant. These
results signal a direct connection between dust and metal-enriched HI
gas and that they are likely cospatial. By comparing our results with
the predictions of different ISM/CGM models, we favor a dusty ISM/CGM
model where dust resides in HI gas clumps and Lyα photons escape
through the low HI covering fraction/column density intraclump medium.
Finally, we investigate the factors that potentially contribute to the
intrinsic scatter in the correlations studied in this work, including
metallicity, outflow kinematics, Lyα production efficiency, and
slit loss. Specifically, we find evidence that scatter in the
relationship between EWLyα and E(B-V) reflects the variation in
the metal-to-H i covering fraction ratio as a function of metallicity
and the effects of outflows on the porosity of the ISM/CGM. Future
simulations incorporating star formation feedback and the radiative
transfer of Lyα photons will provide key constraints on the
spatial distributions of neutral hydrogen gas and dust in the ISM/CGM
structure.
Description:
In this study, we present the first statistical analysis to
characterize the nature and relative strength of the mutual
correlations involving EWLyα , EWLIS, and E(B-V) using rest-UV
spectroscopic measurements of individual galaxies at z∼2. The targets
were observed on 53 multiobject slit masks using the Multi-object
Spectrometer for Infrared Exploration (MOSFIRE) on the Keck I
telescope between 2012 and 2016.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 57 157 *Galaxy properties and line measurements
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Note on table1.dat: The EW values listed are in the rest-frame and in
units of Angstroms. The LIS EW represents the sum of SiII(1260Å),
OI(1302Å)+SiII(1304Å), and CII(1334Å).
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See also:
J/ApJ/786/59 : SED fitting results of HETDEX pilot survey (Hagen+, 2014)
J/ApJS/214/24 : 3D-HST+CANDELS catalog (Skelton+, 2014)
J/ApJ/795/165 : Line ratio in z∼2-3 galaxies from KBSS-MOSFIRE (Steidel+, 2014)
J/ApJ/844/171 : Lyα profile in 43 Green Pea galaxies (Yang+, 2017)
J/ApJ/869/123 : Keck Lyman continuum spectroscopic survey (Steidel+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Field Field identifier; AEGIS, COSMOS or GOODS (N or S)
9- 13 I5 --- ID Galaxy identifier within Field
15- 20 F6.4 --- z [1.65/2.58] Spectroscopic redshift
22- 26 F5.3 mag E(B-V) [0.01/0.44] The (B-V) color excess
28- 32 F5.3 mag e_E(B-V) [0.003/0.05] Uncertainty in E(B-V)
34- 38 F5.1 0.1nm EW-Lya [-47.3/78] Equivalent width of Lyα
40- 43 F4.1 0.1nm e_EW-Lya [0.3/30] Uncertainty in EW-Lya
45 A1 --- l_EW-LIS [>] The 3σ limit flag on EW-LIS
47- 51 F5.1 0.1nm EW-LIS [-46.5/-1.8] Equivalent width of low-ionization
interstellar metal-absorption
53- 55 F3.1 0.1nm e_EW-LIS [0.2/6]? Uncertainty in EW-LIS
57 A1 --- LIS LIS category (1)
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Note (1): Categories as follows:
D = all 3 lines are individually detected (51 occurrences)
P = only 1 or 2 LIS lines are detected at ≥3σ level, and the
LIS EW was inferred based on the method described in Section 3.2.2
(61 occurrences)
C = none of the LIS lines were individually detected, but the combined
line S/N is ≥3 (12 occurrences)
L = none of the LIS lines were individually detected and the combined
line S/N is <3, therefore a 3σ limit is reported (33 occurrences)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 01-Mar-2023