Quasar 2175 Å dust absorbers – II. Correlation analysis and relationship with other absorption line systems

Ma, Jingzhe; Ge, Jian; Prochaska, J. Xavier; Zhang, Shaohua; Ji, Tuo; Zhao, Yinan; Zhou, Hongyan; Lu, Honglin; Schneider, Donald P.

doi:10.1093/mnras/stx3123

Cited by 16 publications

(51 citation statements)

References 93 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Due to the small sample size and relatively large error bars, the observed trends are only found to be correlated at 1 − 2σ significance. The connection of A V and A bump with C i is already well-established for quasar (Ledoux et al 2015;Ma et al 2018) and GRB (Zafar et al 2012;Heintz et al 2019) absorption systems, but here we include the additional information derived from the slope of the extinction, as inferred from R V . The observed trend between A V and W r (λ 1560) indicates that larger amounts of cold gas is found in more dusty sightlines, where the additional trend with R V also suggests that the dust grain size distribution are on average larger in these sightlines as well.…”

Section: Resultsmentioning

confidence: 99%

“…Based on a sample of quasar absorbers selected solely on the basis of the 2175 Å dust extinction feature, Ma et al (2018) found that all such systems are associated with strong absorption features from C i. However, only ≈ 30% of C i-selected absorbers show the characteristic dust bump at a detectable level (Ledoux et al 2015).…”

Section: The Origin Of the 2175 å Dust Extinction Featurementioning

confidence: 99%

“…The cause of this putative discrepancy between the dust content inferred from the extinguished afterglow SED and the gasphase depletion levels, might also be related to a too simplistic view of the location of the dust. Recent studies of GRB and quasar absorbers have for instance found that the visual extinction, A V , and the strength of the 2175 Å extinction bump feature is correlated with the amount of neutral atomic-carbon (C i; Zafar et al 2012;Ledoux et al 2015;Ma et al 2018;Heintz et al 2019). Absorption features from C i are often found to be coincident with H 2 (Srianand et al 2005;Jorgenson et al 2010;Noterdaeme et al 2018) and is therefore believed to be a good tracer of the cold and molecular gas-phase of the ISM.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On the dust properties of high-redshift molecular clouds and the connection to the 2175 Å extinction bump

Heintz

Zafar

et al. 2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We present a study of the extinction and depletion-derived dust properties of gamma-ray burst (GRB) absorbers at 1 < z < 3 showing the presence of neutral carbon (C i). By modelling their parametric extinction laws, we discover a broad range of dust models characterizing the GRB C i absorption systems. In addition to the already well-established correlation between the amount of C i and visual extinction, A V , we also observe a correlation with the total-toselective reddening, R V . All three quantities are also found to be connected to the presence and strength of the 2175 Å dust extinction feature. While the amount of C i is found to be correlated with the SED-derived dust properties, we do not find any evidence for a connection with the depletion-derived dust content as measured from [Zn/Fe] and N(Fe) dust . To reconcile this, we discuss a scenario where the observed extinction is dominated by the composition of dust particles confined in the molecular gas-phase of the ISM. We argue that since the depletion level trace non-carbonaceous dust in the ISM, the observed extinction in GRB C i absorbers is primarily produced by carbon-rich dust in the molecular cloud and is therefore only observable in the extinction curves and not in the depletion patterns. This also indicates that the 2175 Å dust extinction feature is caused by dust and molecules in the cold and molecular gas-phase. This scenario provides a possible resolution to the discrepancy between the depletion-and SED-derived amounts of dust in high-z absorbers.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: The Origin Of the 2175 å Dust Extinction Featurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On the dust properties of high-redshift molecular clouds and the connection to the 2175 Å extinction bump

Heintz

Zafar

et al. 2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…The EWs of main absorption features are listed in Table 7. The neutral carbon detection is particularly interesting, since the appearance of a 2175Å extinction bump at z ∼ 2 has been linked to the presence of C i (e.g., Elíasdóttir et al 2009;Ledoux et al 2015;Ma et al 2018). We Figure 9.…”

Section: Dust-to-gas Ratiomentioning

confidence: 97%

Gravitationally Lensed Quasar SDSS J1442+4055: Redshifts of Lensing Galaxies, Time Delay, Microlensing Variability, and Intervening Metal System at z ∼ 2

Shalyapin

Goicoechea

2019

ApJ

View full text Add to dashboard Cite

We present an r-band photometric monitoring of the two images A and B of the gravitationally lensed quasar SDSS J1442+4055 using the Liverpool Telescope (LT). From the LT light curves between 2015 December and 2018 August, we derive at once a time delay of 25.0 ± 1.5 days (1σ confidence interval; A is leading) and microlensing magnification gradients below 10 −4 mag day −1 . The delay interval is not expected to be affected by an appreciable microlensing-induced bias, so it can be used to estimate cosmological parameters. This paper also focuses on new Gran Telescopio Canarias (GTC) and LT spectroscopic observations of the lens system. We determine the redshift of two bright galaxies around the doubly imaged quasar using LT spectroscopy, while GTC data lead to low-noise individual spectra of A, B, and the main lensing galaxy G1. The G1 spectral shape is accurately matched to an earlytype galaxy template at z = 0.284, and it has potential for further relevant studies. Additionally, the quasar spectra show absorption by metal-rich gas at z ∼ 2. This dusty absorber is responsible for an extinction bump at a rest-frame wavelength of 2209 ± 2Å, which has strengths of ∼ 0.47 and 0.76 mag µm −1 for A and B, respectively. In such intervening system, the dust-to-gas ratio, gas-phase metallicity indicator [Zn/H], and dust depletion level [Fe/Zn] are relatively high.

show abstract

“…The amount of C i has been observed to be correlated with the visual extinction, A V , in the line of sight to quasar and GRB absorbers (Ledoux et al 2015;Ma et al 2018;Heintz et al 2019a), suggesting a common origin for the main extinction-derived dust component and C i (see also Heintz et al 2019b). In Fig.…”

Section: The Connection Between Dust and Molecular Gasmentioning

confidence: 98%

New constraints on the physical conditions in H₂-bearing GRB-host damped Lyman-α absorbers

Heintz

Bolmer

Ledoux

et al. 2019

A&A

View full text Add to dashboard Cite

We report the detections of molecular hydrogen (H 2 ), vibrationally-excited H 2 (H * 2 ), and neutral atomic carbon (C i), an efficient tracer of molecular gas, in two new afterglow spectra of GRBs 181020A (z = 2.938) and 190114A (z = 3.376), observed with X-shooter at the Very Large Telescope (VLT). Both host-galaxy absorption systems are characterized by strong damped Lyman-α absorbers (DLAs) and substantial amounts of molecular hydrogen with log N(H i, H 2 ) = 22.20 ± 0.05, 20.40 ± 0.04 (GRB 181020A) and log N(H i, H 2 ) = 22.15 ± 0.05, 19.44 ± 0.04 (GRB 190114A). The DLA metallicites, depletion levels and dust extinctions are within the typical regimes probed by GRBs with [Zn/H] = −1.57 ± 0.06, [Zn/Fe] = 0.67 ± 0.03, and A V = 0.27 ± 0.02 mag (GRB 181020A) and [Zn/H] = −1.23 ± 0.07, [Zn/Fe] = 1.06 ± 0.08, and A V = 0.36 ± 0.02 mag (GRB 190114A). In addition, we examine the molecular gas content of all known H 2 -bearing GRB-DLAs and explore the physical conditions and characteristics required to simultaneously probe C i and H * 2 . We confirm that H 2 is detected in all C i-and H * 2 -bearing GRB absorption systems, but that these rarer features are not necessarily detected in all GRB H 2 absorbers. We find that a large molecular fraction of f H 2 10 −3 is required for C i to be detected. The defining characteristic for H * 2 to be present is less clear, though a large H 2 column density is an essential factor. We find that the observed line profiles of the molecular-gas tracers are kinematically 'cold', with small velocity offsets of δv < 20 km s −1 from the bulk of the neutral absorbing gas. We then derive the H 2 excitation temperatures of the molecular gas and find that they are relatively low with T ex ≈ 100 − 300 K, however, there could be evidence of warmer components populating the high-J H 2 levels in GRBs 181020A and 190114A. Finally, we demonstrate that even though the X-shooter GRB afterglow campaign has been successful in recovering several H 2 -bearing GRB-host absorbers, this sample is still hampered by a significant dust bias excluding the most dust-obscured H 2 absorbers from identification. C i and H * 2 could open a potential route to identify molecular gas even in low-metallicity or highly dust-obscured bursts, though they are only efficient tracers for the most H 2 -rich GRB-host absorption systems.

show abstract

Quasar 2175 Å dust absorbers – II. Correlation analysis and relationship with other absorption line systems

Cited by 16 publications

References 93 publications

On the dust properties of high-redshift molecular clouds and the connection to the 2175 Å extinction bump

On the dust properties of high-redshift molecular clouds and the connection to the 2175 Å extinction bump

Gravitationally Lensed Quasar SDSS J1442+4055: Redshifts of Lensing Galaxies, Time Delay, Microlensing Variability, and Intervening Metal System at z ∼ 2

New constraints on the physical conditions in H₂-bearing GRB-host damped Lyman-α absorbers

Contact Info

Product

Resources

About

Quasar 2175 Å dust absorbers – II. Correlation analysis and relationship with other absorption line systems

Cited by 16 publications

References 93 publications

On the dust properties of high-redshift molecular clouds and the connection to the 2175 Å extinction bump

On the dust properties of high-redshift molecular clouds and the connection to the 2175 Å extinction bump

Gravitationally Lensed Quasar SDSS J1442+4055: Redshifts of Lensing Galaxies, Time Delay, Microlensing Variability, and Intervening Metal System at z ∼ 2

New constraints on the physical conditions in H2-bearing GRB-host damped Lyman-α absorbers

Contact Info

Product

Resources

About

New constraints on the physical conditions in H₂-bearing GRB-host damped Lyman-α absorbers