Cold gas and a Milky Way-type 2175-Å bump in a metal-rich and highly depleted absorption system

Jingzhe Ma, Paul Caucal, Pasquier Noterdaeme, Jian Ge, J. Xavier Prochaska, Tuo Ji, Shaohua Zhang, Hadi Rahmani, Peng Jiang, Donald P. Schneider, Britt Lundgren, Isabelle Pâris

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

We report the detection of a strong MilkyWay-type 2175-Å extinction bump at z = 2.1166 in the quasar spectrum towards SDSS J121143.42+083349.7 from the Sloan Digital Sky Survey Data Release 10.We conduct followup observations with the Echelle Spectrograph and Imager on-board the Keck II telescope and the Ultraviolet and Visual Echelle Spectrograph on the Very Large Telescope. This 2175-Å absorber is remarkable in that we simultaneously detect neutral carbon (C I), neutral chlorine (Cl I), and carbon monoxide (CO). It also qualifies as a damped Lyman α system. The J1211+0833 absorber is found to be metal rich and has a dust depletion pattern resembling that of the Milky Way disc clouds. We use the column densities of the CI fine structure states and the CII/C I ratio (under the assumption of ionization equilibrium) to derive the temperature and volume density in the absorbing gas. A CLOUDY photoionization model is constructed, which utilizes additional atoms/ions to constrain the physical conditions. The inferred physical conditions are consistent with a canonical cold (T ~ 100 K) neutral medium with a high density (n(H I) ~ 100 cm-3) and a slightly higher pressure than the local interstellar medium. Given the simultaneous presence of C I, CO, and the 2175-Å bump, combined with the high metallicity, high dust depletion level, and overall low ionization state of the gas, the absorber towards J1211+0833 supports the scenario that the presence of the bump requires an evolved stellar population.

Original languageEnglish (US)
Pages (from-to)1751-1766
Number of pages16
JournalMonthly Notices of the Royal Astronomical Society
Volume454
Issue number2
DOIs
StatePublished - Jan 1 2015

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cold gas
absorbers
carbon monoxide
spectrographs
metal
depletion
ionization
chlorine monoxide
dust
gas
telescopes
metals
gases
quasars
metallicity
chlorine
photoionization
extinction
fine structure
ion

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Ma, Jingzhe ; Caucal, Paul ; Noterdaeme, Pasquier ; Ge, Jian ; Prochaska, J. Xavier ; Ji, Tuo ; Zhang, Shaohua ; Rahmani, Hadi ; Jiang, Peng ; Schneider, Donald P. ; Lundgren, Britt ; Pâris, Isabelle. / Cold gas and a Milky Way-type 2175-Å bump in a metal-rich and highly depleted absorption system. In: Monthly Notices of the Royal Astronomical Society. 2015 ; Vol. 454, No. 2. pp. 1751-1766.
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abstract = "We report the detection of a strong MilkyWay-type 2175-{\AA} extinction bump at z = 2.1166 in the quasar spectrum towards SDSS J121143.42+083349.7 from the Sloan Digital Sky Survey Data Release 10.We conduct followup observations with the Echelle Spectrograph and Imager on-board the Keck II telescope and the Ultraviolet and Visual Echelle Spectrograph on the Very Large Telescope. This 2175-{\AA} absorber is remarkable in that we simultaneously detect neutral carbon (C I), neutral chlorine (Cl I), and carbon monoxide (CO). It also qualifies as a damped Lyman α system. The J1211+0833 absorber is found to be metal rich and has a dust depletion pattern resembling that of the Milky Way disc clouds. We use the column densities of the CI fine structure states and the CII/C I ratio (under the assumption of ionization equilibrium) to derive the temperature and volume density in the absorbing gas. A CLOUDY photoionization model is constructed, which utilizes additional atoms/ions to constrain the physical conditions. The inferred physical conditions are consistent with a canonical cold (T ~ 100 K) neutral medium with a high density (n(H I) ~ 100 cm-3) and a slightly higher pressure than the local interstellar medium. Given the simultaneous presence of C I, CO, and the 2175-{\AA} bump, combined with the high metallicity, high dust depletion level, and overall low ionization state of the gas, the absorber towards J1211+0833 supports the scenario that the presence of the bump requires an evolved stellar population.",
author = "Jingzhe Ma and Paul Caucal and Pasquier Noterdaeme and Jian Ge and Prochaska, {J. Xavier} and Tuo Ji and Shaohua Zhang and Hadi Rahmani and Peng Jiang and Schneider, {Donald P.} and Britt Lundgren and Isabelle P{\^a}ris",
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Ma, J, Caucal, P, Noterdaeme, P, Ge, J, Prochaska, JX, Ji, T, Zhang, S, Rahmani, H, Jiang, P, Schneider, DP, Lundgren, B & Pâris, I 2015, 'Cold gas and a Milky Way-type 2175-Å bump in a metal-rich and highly depleted absorption system', Monthly Notices of the Royal Astronomical Society, vol. 454, no. 2, pp. 1751-1766. https://doi.org/10.1093/mnras/stv2073

Cold gas and a Milky Way-type 2175-Å bump in a metal-rich and highly depleted absorption system. / Ma, Jingzhe; Caucal, Paul; Noterdaeme, Pasquier; Ge, Jian; Prochaska, J. Xavier; Ji, Tuo; Zhang, Shaohua; Rahmani, Hadi; Jiang, Peng; Schneider, Donald P.; Lundgren, Britt; Pâris, Isabelle.

In: Monthly Notices of the Royal Astronomical Society, Vol. 454, No. 2, 01.01.2015, p. 1751-1766.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Cold gas and a Milky Way-type 2175-Å bump in a metal-rich and highly depleted absorption system

AU - Ma, Jingzhe

AU - Caucal, Paul

AU - Noterdaeme, Pasquier

AU - Ge, Jian

AU - Prochaska, J. Xavier

AU - Ji, Tuo

AU - Zhang, Shaohua

AU - Rahmani, Hadi

AU - Jiang, Peng

AU - Schneider, Donald P.

AU - Lundgren, Britt

AU - Pâris, Isabelle

PY - 2015/1/1

Y1 - 2015/1/1

N2 - We report the detection of a strong MilkyWay-type 2175-Å extinction bump at z = 2.1166 in the quasar spectrum towards SDSS J121143.42+083349.7 from the Sloan Digital Sky Survey Data Release 10.We conduct followup observations with the Echelle Spectrograph and Imager on-board the Keck II telescope and the Ultraviolet and Visual Echelle Spectrograph on the Very Large Telescope. This 2175-Å absorber is remarkable in that we simultaneously detect neutral carbon (C I), neutral chlorine (Cl I), and carbon monoxide (CO). It also qualifies as a damped Lyman α system. The J1211+0833 absorber is found to be metal rich and has a dust depletion pattern resembling that of the Milky Way disc clouds. We use the column densities of the CI fine structure states and the CII/C I ratio (under the assumption of ionization equilibrium) to derive the temperature and volume density in the absorbing gas. A CLOUDY photoionization model is constructed, which utilizes additional atoms/ions to constrain the physical conditions. The inferred physical conditions are consistent with a canonical cold (T ~ 100 K) neutral medium with a high density (n(H I) ~ 100 cm-3) and a slightly higher pressure than the local interstellar medium. Given the simultaneous presence of C I, CO, and the 2175-Å bump, combined with the high metallicity, high dust depletion level, and overall low ionization state of the gas, the absorber towards J1211+0833 supports the scenario that the presence of the bump requires an evolved stellar population.

AB - We report the detection of a strong MilkyWay-type 2175-Å extinction bump at z = 2.1166 in the quasar spectrum towards SDSS J121143.42+083349.7 from the Sloan Digital Sky Survey Data Release 10.We conduct followup observations with the Echelle Spectrograph and Imager on-board the Keck II telescope and the Ultraviolet and Visual Echelle Spectrograph on the Very Large Telescope. This 2175-Å absorber is remarkable in that we simultaneously detect neutral carbon (C I), neutral chlorine (Cl I), and carbon monoxide (CO). It also qualifies as a damped Lyman α system. The J1211+0833 absorber is found to be metal rich and has a dust depletion pattern resembling that of the Milky Way disc clouds. We use the column densities of the CI fine structure states and the CII/C I ratio (under the assumption of ionization equilibrium) to derive the temperature and volume density in the absorbing gas. A CLOUDY photoionization model is constructed, which utilizes additional atoms/ions to constrain the physical conditions. The inferred physical conditions are consistent with a canonical cold (T ~ 100 K) neutral medium with a high density (n(H I) ~ 100 cm-3) and a slightly higher pressure than the local interstellar medium. Given the simultaneous presence of C I, CO, and the 2175-Å bump, combined with the high metallicity, high dust depletion level, and overall low ionization state of the gas, the absorber towards J1211+0833 supports the scenario that the presence of the bump requires an evolved stellar population.

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DO - 10.1093/mnras/stv2073

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