J/MNRAS/482/2731 Metals, depletion, and dimming: decrypting dust (Zafar+, 2019)
Metals, depletion, and dimming: decrypting dust.
Zafar T., Moller P.
<Mon. Not. R. Astron. Soc., 482, 2731-2738 (2019)>
=2019MNRAS.482.2731Z 2019MNRAS.482.2731Z (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium ; Abundances ; Extinction ; QSOs ; GRB
Keywords: ISM: abundances - dust, extinction - galaxies: high-redshift -
quasars: general
Abstract:
Dust plays a pivotal role in the chemical enrichment of the
interstellar medium. In the era of mid-/high-resolution spectra and
multiband spectral energy distributions, testing extinctions against
gas and dust-phase properties is becoming possible. In order to test
relations between metals, dust, and depletions, and comparing those to
the Local Group (LG) relations, we build a sample of 93 γ-ray
bursts and quasar absorbers (the largest sample so far) which have
extinction and elemental column density measurements available. We
find that extinctions and total column density of the volatile
elements (Zn,S) are correlated [with a best fit of dust-to-metals
(DTM) 4.05x10-22mag.cm2] and consistent with the LG DTM relation.
The refractory elements (Fe,Si) follow a similar, but less
significant, relation offset about 1dex from the LG relation. On the
assumption that depletion on to dust grains is the cause, we compute
the total (gas+dust-phase) column density and find a remarkable
agreement with the LG DTM relation: a best fit of
4.91x10-22mag.cm2. We then use our results to compute the amount of
'intervening metal from unknown sources' in random sightlines out to
redshifts of z=5. Those metals implicate the presence of dust and give
rise to an average 'cosmic dust dimming' effect that we express as a
function of redshift, CDD(z). The CDD is unimportant out to redshifts
of about 3, but because it is cumulative it becomes significant at
redshifts z=3-5. Our results in this paper are based on a minimum of
assumptions and effectively relying on observations.
Description:
We searched the literature carefully and selected all published
GRB-DLAs and QSO-DLAs sightlines conforming to our requirements which
are as follows. The object must have spectral energy distributions
(SEDs) and optical spectroscopic data available with measurements of
AV, column densities of ZnII and FeII, or of SII and SiII. The GRBs
are selected only if they had their optical extinction derived from
simultaneous SED fitting to X-ray-to-optical/NIR data using either a
single or broken power law (see Greiner et al. 2011A&A...526A..30G 2011A&A...526A..30G;
Zafar et al. 2011A&A...532A.143Z 2011A&A...532A.143Z; Schady et al. 2012A&A...537A..15S 2012A&A...537A..15S;
Covino et al. 2013MNRAS.432.1231C 2013MNRAS.432.1231C; Bolmer et al. 2018A&A...609A..62B 2018A&A...609A..62B;
Zafar et al. 2018MNRAS.479.1542Z 2018MNRAS.479.1542Z for discussion on AV determination).
This is a reliable method to determine extinctions at higher redshifts
where the intrinsic slopes are constrained by the X-ray data.
In total, this makes up a sample of 46 GRBs (see Table 1) and 47
QSO-DLAs (see Table 2), i.e. a total of 93 independent sightlines.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 109 48 GRBs data used to estimate dust-to-metals
ratios and N(Fe,Si)dust
refs1.dat 242 47 References for table1
table2.dat 103 47 QSO DLAs and sub-DLAs data used to estimate
dust-to-metals ratios and N(Fe,Si)dust
refs2.dat 48 32 References for table2
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- GRB GRB name (GRB YYMMDDA)
13 A1 --- l_AV Limit flag on AV
15- 18 F4.2 mag AV Extinction in the V band
20- 23 F4.2 mag E_AV ? Upper error on AV
25- 28 F4.2 mag e_AV ? Lower error on AV
30- 35 F6.4 --- zabs Redshift
37 A1 --- l_NHI Limit flag on NHI
39- 43 F5.2 [cm-2] NHI ? HI column density
45- 48 F4.2 [cm-2] e_NHI ? Error on NHI
50 A1 --- l_NZnII Limit flag on NZnII
52- 56 F5.2 [cm-2] NZnII ? ZnII column density
58- 61 F4.2 [cm-2] e_NZnII ? Error on NZnII
63 A1 --- l_NFeII Limit flag on NFeII
65- 69 F5.2 [cm-2] NFeII ? FeII column density
71- 74 F4.2 [cm-2] e_NFeII ? Error on NFeII
76 A1 --- l_NSII Limit flag on NSII
78- 82 F5.2 [cm-2] NSII ? SII column density
84- 87 F4.2 [cm-2] e_NSII ? Error on NSII
89 A1 --- l_NSiII Limit flag on NSiII
91- 95 F5.2 [cm-2] NSiII ? SiII column density
97-100 F4.2 [cm-2] e_NSiII ? Error on NSiII
102-109 A8 --- Ref References to original data, in refs1.dat file
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- QSO QSO name (QSO HHMM+DDMM)
15 A1 --- l_AV [~<>] Limit flag on AV
17- 20 F4.2 mag AV Extinction in the V band
22- 25 F4.2 mag E_AV ? Upper error on AV
27- 30 F4.2 mag e_AV ? Lower error on AV
32- 36 F5.3 --- zabs Redshift
38- 42 F5.2 [cm-2] NHI ? HI column density
44- 47 F4.2 [cm-2] e_NHI ? Error on NHI
49 A1 --- l_NZnII Limit flag on NZnII
51- 55 F5.2 [cm-2] NZnII ? ZnII column density
57- 60 F4.2 [cm-2] e_NZnII ? Error on NZnII
62 A1 --- l_NFeII Limit flag on NFeII
64- 68 F5.2 [cm-2] NFeII FeII column density
70- 73 F4.2 [cm-2] e_NFeII ? Error on NFeII
75- 79 F5.2 [cm-2] NSII ? SII column density
81- 84 F4.2 [cm-2] e_NSII ? Error on NSII
86 A1 --- l_NSiII Limit flag on NSiII
88- 92 F5.2 [cm-2] NSiII ? SiII column density
94- 97 F4.2 [cm-2] e_NSiII ? Error on NSiII
99-103 A5 --- Ref References to original data, in refs2.dat file
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Byte-by-byte Description of file: refs1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 50 A27 --- Aut Author's name
52-242 A191 --- Com Comments
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Byte-by-byte Description of file: refs2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 48 A25 --- Aut Author's name
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 27-Jun-2022