Detection of a Multiphase Intragroup Medium: Results from the COS-IGrM Survey

Tyler McCabe; Sanchayeeta Borthakur; Timothy Heckman; Jason Tumlinson; Rongmon Bordoloi; Romeel Dave

doi:10.3847/1538-4357/ac283c

Detection of a Multiphase Intragroup Medium: Results from the COS-IGrM Survey

The Astrophysical Journal ◽

10.3847/1538-4357/ac283c ◽

2021 ◽

Vol 923 (2) ◽

pp. 189

Author(s):

Tyler McCabe ◽

Sanchayeeta Borthakur ◽

Timothy Heckman ◽

Jason Tumlinson ◽

Rongmon Bordoloi ◽

...

Keyword(s):

Hubble Space Telescope ◽

Space Telescope ◽

Volume Filling ◽

Wide Range ◽

Ideal Tracer ◽

The Ideal

Abstract We present the results of the Cosmic Origins Spectrograph-Intragroup Medium (COS-IGrM) Survey that used the COS on the Hubble Space Telescope to observe a sample of 18 UV bright quasars, each probing the IGrM of a galaxy group. We detect Lyα, C ii, N v, Si ii, Si iii, and O vi in multiple sightlines. The highest ionization species detected in our data is O vi, which was detected in eight out of 18 quasar sightlines. The wide range of ionization states observed provide evidence that the IGrM is patchy and multiphase. We find that the O vi detections generally align with radiatively cooling gas between 105.8 and 106 K. The lack of O vi detections in 10 of the 18 groups illustrates that O vi may not be the ideal tracer of the volume filling component of the IGrM. Instead, it either exists at trace levels in a hot IGrM or is generated in the boundary between the hotter IGrM and cooler gas.

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Photometric Calibrators for All-Sky Surveys: The GSPC-II Program

Symposium - International Astronomical Union ◽

10.1017/s0074180900047525 ◽

1994 ◽

Vol 161 ◽

pp. 301-303

Author(s):

A. Ferrari ◽

E.D. Siciliano ◽

A. Pizzuti ◽

B. Bucciarelli ◽

G. Massone ◽

...

Keyword(s):

Hubble Space Telescope ◽

Stellar Populations ◽

Galactic Structure ◽

Mission Planning ◽

Space Telescope ◽

Sky Surveys ◽

Star Catalog ◽

Wide Range ◽

The Uk ◽

Guide Star

Accurate astrometric and photometric calibrations of all-sky photographic surveys, such as the Palomar Quick-V survey and the UK SERC-J survey, digitised for the construction of the Hubble Space Telescope Guide Star Catalog, are of extreme astrophysical value. Their wide range of applications includes, for example, galactic structure, stellar populations, extragalactic studies, and deep sky catalogs for mission planning and telescope operations. The Guide Star Photometric Catalog (GSPC-I, Lasker et al. 1988) provides stellar calibration sequences, placed approximately in the center of each survey plate, with a limiting magnitude of V = 15 mag. The goal of our program is to extend these calibrators to V = 20 mag in the Johnson-Kron-Cousins B, V and R passbands, with an accuracy of 0.05 mag. This is accomplished by taking CCD frames centered on the faintest star of each GSPC-I sequence. Typically, both long and short exposures are acquired in each field in order to link the bright and faint ends of the sequence.

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Inflowing gas in the central parsec of M81

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1761 ◽

2019 ◽

Vol 488 (1) ◽

pp. 1199-1210 ◽

Cited By ~ 1

Author(s):

Nick Devereux

Keyword(s):

Hubble Space Telescope ◽

Line Emission ◽

Visible Spectrum ◽

Emission Lines ◽

Extended Source ◽

Space Telescope ◽

X Ray ◽

Wide Range ◽

Low Metallicity ◽

Central Parsec

Abstract Spectroscopic observations of the Seyfert 1/Liner nucleus of M81, obtained recently with the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope(HST), have revealed an ultraviolet (UV)–visible spectrum rich with emission lines of a variety of widths, ionization potentials, and critical densities, including several in the UV that have not previously been reported. Even at the highest angular resolution currently achievable with HST, the broad-line region of M81 cannot be uniquely defined on the basis of commonly used observables such as the full width at half-maximum of the emission lines, or ratios of various emission lines. Numerous broad forbidden lines complicate interpretation of the spectra. At least three separate line-emitting components are inferred. Firstly, a large, highly ionized, low-density, low-metallicity H+ region producing the broad Balmer lines. Located within the H+ region are smaller condensations spanning a wide range in density, and the source of forbidden line emission through collisional excitation of the respective ions. Intermingled with the H+ region and the condensations is a curious extended source of time-variable C iv λ1548 emission. Collectively, these observations can be qualitatively understood in the context of a shock-excited jet cavity within a large H+ region that is photoionized by the central UV–X-ray source. The H+ region contains ∼500 M⊙ of low-metallicity gas that is dynamically unstable to inflow. At the current rate, the available H+ gas can sustain the advection-dominated accretion flow that powers the central UV–X-ray source for 105 yr.

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