Cosmic Flows: Green Bank Telescope and Parkes H i observations

Courtois, H. M.; Tully, R. Brent; Макаров, Д. И.; Митронова, С. Н.; Koribalski, B. S.; Караченцев, И. Д.; Fisher, J. Richard

doi:10.1111/j.1365-2966.2011.18515.x

Cited by 64 publications

(76 citation statements)

References 40 publications

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“…We selected two star-forming dwarf irregular galaxies, namely Sextans A of the Antlia-Sextans group (van den Bergh 1999), with a radial velocity RV = 323 km s −1 (Courtois et al 2011) and distance =1.32 Mpc (Dolphin et al 2003), and the Local Group member IC 1613 with an RV = −234 km s −1 (Lu et al 1993) and distance =0.73 Mpc (Dolphin et al 2001). The metallicities of these galaxies are low, with [O/H] −1.2 for Sextans A and [O/H] −0.8 for IC 1613 (Skillman et al 1989).…”

Section: Target Selectionmentioning

confidence: 99%

Identification of red supergiants in nearby galaxies with mid-IR photometry

Britavskiy

Bonanos

Mehner

et al. 2014

A&A

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Context. The role of episodic mass loss in massive-star evolution is one of the most important open questions of current stellar evolution theory. Episodic mass loss produces dust and therefore causes evolved massive stars to be very luminous in the mid-infrared and dim at optical wavelengths. Aims. We aim to increase the number of investigated luminous mid-IR sources to shed light on the late stages of these objects. To achieve this we employed mid-IR selection criteria to identity dusty evolved massive stars in two nearby galaxies. Methods. The method is based on mid-IR colors, using 3.6 μm and 4.5 μm photometry from archival Spitzer Space Telescope images of nearby galaxies and J-band photometry from 2MASS. We applied our criteria to two nearby star-forming dwarf irregular galaxies, Sextans A and IC 1613, selecting eight targets, which we followed-up with spectroscopy. Results. Our spectral classification and analysis yielded the discovery of two M-type supergiants in IC 1613, three K-type supergiants and one candidate F-type giant in Sextans A, and two foreground M giants. We show that the proposed criteria provide an independent way for identifying dusty evolved massive stars that can be extended to all nearby galaxies with available Spitzer/IRAC images at 3.6 μm and 4.5 μm.

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Section: Target Selectionmentioning

confidence: 99%

Identification of red supergiants in nearby galaxies with mid-IR photometry

Britavskiy

Bonanos

Mehner

et al. 2014

A&A

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“…New distance surveys, from which peculiar velocities can be inferred, have emerged in the recent years like SFI++ (Masters et al 2006;Springob et al 2007Springob et al , 2009), 6dFv (Campbell et al 2014), CosmicFlows-1 (Courtois et al 2011), CosmicFlows-2 (Tully et al 2013). More surveys are coming online such as TAIPAN/WALLABY (Beutler et al 2011;Duffy et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Bayesian 3D velocity field reconstruction with virbius

Lavaux

2016

Mon. Not. R. Astron. Soc.

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I describe a new Bayesian based algorithm to infer the full three dimensional velocity field from observed distances and spectroscopic galaxy catalogues. In addition to the velocity field itself, the algorithm reconstructs true distances, some cosmological parameters and specific non-linearities in the velocity field. The algorithm takes care of selection effects, miscalibration issues and can be easily extended to handle direct fitting of, e.g., the inverse Tully-Fisher relation. I first describe the algorithm in details alongside its performances. This algorithm is implemented in the VIRBIuS (VelocIty Reconstruction using Bayesian Inference Software) software package. I then test it on different mock distance catalogues with a varying complexity of observational issues. The model proved to give robust measurement of velocities for mock catalogues of 3,000 galaxies. I expect the core of the algorithm to scale to tens of thousands galaxies. It holds the promises of giving a better handle on future large and deep distance surveys for which individual errors on distance would impede velocity field inference.

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“…That quantity is transformed into the more physically motivated parameter W mx , which is the same width corrected for the slight relativistic broadening and for broadening due to finite spectral resolution, corrected for inclination and so is effectively twice the maximum rotation velocity. Technical details of this process are provided by Courtois et al (2009) and Courtois et al (2011), and reviewed in .…”

Section: The Cosmic Flows Programmentioning

confidence: 99%

“…Two sub-projects of CF, at Green Bank in the USA and at Parkes in Australia (Courtois et al 2011), complete the archives for targets without previous observations adequate for the Tully-Fisher method of distance measurements (Tully & Fisher 1977). The latest update of this catalog is published in Courtois & Tully (2015).…”

Section: The Cosmic Flows Programmentioning

confidence: 99%

“…In that cause, they have measured tens of thousands of galaxy line widths with a new method described by Courtois et al (2009) and Courtois et al (2011). Briefly, for each galaxy, they evaluate the line width parameter Wm50, which measures the HI profile width at 50% of the mean flux within the velocity range encompassing 90% of the total HI flux.…”

Section: The Cosmic Flows Programmentioning

confidence: 99%

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Giant disk galaxies : Where environment trumps mass in galaxy evolution

Courtois

2015

Proc. IAU

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We identify some of the most HI massive and fastest rotating disk galaxies in the local universe with the aim of probing the processes that drive the formation of these extreme disk galaxies. By combining data from the Cosmic Flows project, which has consistently reanalyzed archival galaxy HI profiles, and 3.6µm photometry obtained with the Spitzer Space Telescope, with which we can measure stellar mass, we use the baryonic Tully-Fisher (BTF) relationship to explore whether these massive galaxies are distinct. We discuss several results, but the most striking is the systematic offset of the HI-massive sample above the BTF. These galaxies have both more gas and more stars in their disks than the typical disk galaxy of similar rotational velocity. The "condensed" baryon fraction, f C , the fraction of the baryons in a dark matter halo that settle either as cold gas or stars into the disk, is twice as high in the HImassive sample than typical, and almost reaches the universal baryon fraction in some cases, suggesting that the most extreme of these galaxies have little in the way of a hot baryonic component or cold baryons distributed well outside the disk. In contrast, the star formation efficiency, measured as the ratio of the mass in stars to that in both stars and gas, shows no difference between the HI-massive sample and the typical disk galaxies. We conclude that the star formation efficiency is driven by an internal, self-regulating process, while f C is affected by external factors. Neither the morphology nor the star formation rate of these galaxies is primarily determined by either their dark or stellar mass. We also found that the most massive HI detected galaxies are located preferentially in filaments. We present the first evidence of an environmental effect on galaxy evolution using a dynamical definition of a filament.

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Cosmic Flows: Green Bank Telescope and Parkes H i observations

Cited by 64 publications

References 40 publications

Identification of red supergiants in nearby galaxies with mid-IR photometry

Identification of red supergiants in nearby galaxies with mid-IR photometry

Bayesian 3D velocity field reconstruction with virbius

Giant disk galaxies : Where environment trumps mass in galaxy evolution

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