Low‐ and High‐Ionization Absorption Properties of Mg
                    <scp>ii</scp>
                    Absorption–selected Galaxies at Intermediate Redshifts. I. General Properties

Churchill, Christopher W.; Mellon, Richard R.; Charlton, Jane C.; Jannuzi, Buell T.; Kirhakos, Sofia; Steidel, Charles C.; Schneider, Donald P.

doi:10.1086/317343

Cited by 132 publications

(115 citation statements)

References 47 publications

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“…Detection and significance levels follow the formalism of Schneider et al (1993) and Churchill et al (2000a). In addition, intervening and intrinsic Mgii and Civ absorption systems serendipitously identified in the spectra that were not targeted in this survey are listed in Table A1.…”

Section: Agn and Background Quasar Spectroscopymentioning

confidence: 99%

Probing the circumgalactic medium of active galactic nuclei with background quasars

Kacprzak¹,

Churchill²,

Murphy³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We performed a detailed study of the extended cool gas, traced by Mg ii absorption [W r (2796) 0.3 Å], surrounding 14 narrow-line active galactic nuclei (AGNs) at 0.12 z 0.22 using background quasar sight-lines. The background quasars probe the AGNs at projected distances of 60 D 265 kpc. We find that, between 100 D 200 kpc, AGNs appear to have lower Mg ii gas covering fractions (0.09−0.08 ) than quasars (0.47−0.15 ) and possibly lower than in active field galaxies (0.25−0.09 ). We do not find a statistically significant azimuthal angle dependence for the Mg ii covering fraction around AGNs, though the data hint at one. We also study the 'down-the-barrel' outflow properties of the AGNs themselves and detect intrinsic NaiD absorption in 8/8 systems and intrinsic Mg ii absorption in 2/2 systems, demonstrating that the AGNs have significant reservoirs of cool gas. We find that 6/8 NaiD and 2/2 Mg ii intrinsic systems contain blueshifted absorption with ∆v > 50 km s −1 , indicating outflowing gas. The 2/2 intrinsic Mg ii systems have outflow velocities a factor of ∼ 4 higher than the NaiD outflow velocities. Our results are consistent with AGN-driven outflows destroying the cool gas within their halos, which dramatically decreases their cool gas covering fraction, while star-burst driven winds are expelling cool gas into their circumgalactic media (CGM). This picture appears contrary to quasar-quasar pair studies which show that the quasar CGM contains significant amounts of cool gas whereas intrinsic gas found 'downthe-barrel' of quasars reveals no cool gas. We discuss how these results are complementary and provide support for the AGN unified model.

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Section: Agn and Background Quasar Spectroscopymentioning

confidence: 99%

Probing the circumgalactic medium of active galactic nuclei with background quasars

Kacprzak¹,

Churchill²,

Murphy³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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“…Photoionized regions with sizes of 1-65 kpc, and with −1.5 log U −0.6, could produce the Nv as well as the strong Civ and O vi absorption. This system does not contribute significantly to the Lyman limit break, again distinguishing it from strong Mg ii absorbers (Churchill et al 2000a). …”

Section: System Amentioning

confidence: 87%

“…The continuum fitting was performed on the extracted spectrum using standard methods (Churchill & Vogt 2001). Absorption lines were detected using the formalism of Schneider et al (1993) and Churchill et al (2000a).…”

Section: Hst/stis Qso Spectroscopymentioning

confidence: 99%

The Multi-Phase Absorption Systems Toward PG 1206 + 459

Ding

2003

Astrophysics and Space Science Library

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A high-resolution (R = 30, 000) ultraviolet spectrum is presented, which covers Lyα and many low-, intermediate-, and high-ionization transitions in the three Mg ii-selected absorption systems toward the quasar PG 1206 + 459. Three systems (A, B, and C), which are clustered within 1500 km s −1 at z ∼ 0.93, were originally identified in a spectrum obtained with the High Resolution Spectrograph (HIRES) on the Keck I telescope. A WIYN Gunn i-band image of the quasar field and spectroscopy of two galaxy candidates are presented. A multi-phase medium is seen in all three systems, consistent with smaller, denser clouds producing low-ionization transitions (Mg ii, Feii, and Si ii) and larger, diffuse, photoionized clouds giving rise to higher-ionization transitions (Civ, Nv, 1 Based in part on observations obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among Caltech, the University of California, and NASA. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.2 Based in part on observations obtained with the NASA/ESA Hubble Space Telescope, which is operated by the STScI for the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.3 Based in part on observations obtained with the WIYN 3.5-m telescope, a joint facility of the University of Wisconsin-Madison, Indiana University, Yale University, and the National Optical Astronomy Observatories. (1) System A, a multi-cloud, weak Mg ii absorber at z = 0.9254, requires a super-solar metallicity in both low-and high-ionization phases, unless an α-group enhancement is included. The low-ionization absorption is produced in clouds with sizes of 10-70 pc, which are surrounded in velocity space by broader, high-ionization components. With the unusually complex velocity structure resolved in the Nv profiles, this system is unlikely to represent a traditional galaxy disk/corona. The most likely candidate host galaxy is a ∼ 2L * , apparently warped, spiral at an impact parameter of 43h −1 kpc. (2) System B, at z = 0.9276, has the strongest Mg ii absorption and has an approximately solar metallicity in the low-ionization phase. The smooth, broad high-ionization profiles may indicate a coronal structure similar to that of the Milky Way. The redshift of an L * galaxy (z = 0.9289), at an impact parameter of 38h −1 kpc is consistent with the redshift of this system. (3) System C, at z = 0.9342, has a single component in Mg ii, separated from the other two systems by ∼ +1000 km s −1 . The Lyα profile is not aligned with the Mg ii, requiring an additional velocity component offset by −40 km s −1 . System C lacks the small, low-ionization cloud characteristic of an isolated single-cloud, weak Mg ii absorber. Its absorption properties are similar to the "satellite clouds" of classic strong Mg ii absorbers, so this could be a high-velocity cloud in the galaxy group responsible for the systems, possibly related to a 0.2L * galaxy at an impact parameter of 43h −1 kpc.

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“…Absorption line systems traced by Mg iiλλ2796,2803 doublet in the quasar spectra provide a direct tracer of cool, T ∼ 10 4 K, gas within gaseous haloes and circumgalactic medium (CGM) surrounding galaxies over a wide range of H i column densities, 16 log [N (H i) cm −2 ] 22 (Bergeron 1986;Churchill et al 2000;Rao & Turnshek 2000;Rigby et al 2002), out to projected distances of ∼ 200 kpc (e.g., Kacprzak et al 2008;Chen et al 2010a,b;Bordoloi et al 2011;Nielsen et al 2013b). The paradigm developed thus far is that the Mg ii absorbers are linked with either of the galactic-scale outflows originating from their host galaxies (Bouché et al 2006;Tremonti et al 2007;Weiner et al 2009;Martin & Bouché 2009;Noterdaeme et al 2010;Chelouche & Bowen 2010; ⋆ E-mail: rjoshi@iucaa.in(RJ) Rubin et al 2010;Lundgren et al 2012;Bordoloi et al 2014), dynamical mergers or filamentary accretion on to galaxies (Steidel et al 2002;Chen et al 2010a;Kacprzak et al 2010Kacprzak et al , 2011Kacprzak et al , 2012Martin et al 2012;Rubin et al 2012) and high velocity clouds [HVCs] (Richter 2012;Herenz et al 2013).…”

Section: Introductionmentioning

confidence: 99%

“…In efforts to determine physical properties of galaxies associated with Mg ii absorbers (hereinafter Mg ii galaxies), the rest-frame equivalent width (W2796) of Mg ii absorption is found to be anticorrelated with impact parameter (ρ), at ∼ 7.9σ level (Bergeron & Boissé 1991;Lanzetta & Bowen 1990;Steidel 1995;Churchill et al 2000;Kacprzak et al 2008;Chen et al 2010a;Rao et al 2011;Nielsen et al 2013b;Kacprzak et al 2013). This has led to the suggestions that the Mg ii absorption could originate from the extended halos of normal galaxies with unit covering factor c 2016 The Authors for the absorbing gas (see e.g., Petitjean & Bergeron 1990;Srianand & Khare 1994).…”

Section: Introductionmentioning

confidence: 99%

[O ii] nebular emission from Mg ii absorbers: star formation associated with the absorbing gas

Joshi

Srianand

Petitjean

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present nebular emission associated with 198 strong Mg ii absorbers at 0.35 z 1.1 in the fibre spectra of quasars from the Sloan Digital Sky Survey. Measured and their z evolution are consistent with those of galaxies detected in deep surveys. Based on the median stacked spectra, we infer the average metallicity (log Z ∼8.3), ionization parameter (log q ∼7.5) and stellar mass (log (M/M ⊙ )∼9.3). The Mg ii systems with nebular emission typically have W 2796 2Å, Mg ii doublet ratio close to 1 and W(Fe iiλ2600)/W 2796 ∼ 0.5 as often seen in damped Lyα and 21-cm absorbers at these redshifts. This is the biggest reported sample of [O ii] emission from Mg ii absorbers at low impact parameters ideally suited for probing various feedback processes at play in z 1 galaxies.

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Low‐ and High‐Ionization Absorption Properties of Mg ii Absorption–selected Galaxies at Intermediate Redshifts. I. General Properties

Cited by 132 publications

References 47 publications

Probing the circumgalactic medium of active galactic nuclei with background quasars

Probing the circumgalactic medium of active galactic nuclei with background quasars

The Multi-Phase Absorption Systems Toward PG 1206 + 459

[O ii] nebular emission from Mg ii absorbers: star formation associated with the absorbing gas

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