ERRATUM: “SFI++. II. A NEW
                    <i>I</i>
                    -BAND TULLY-FISHER CATALOG, DERIVATION OF PECULIAR VELOCITIES AND DATA SET PROPERTIES” (2007, ApJS, 172, 599)

The core of the nearby galaxy NGC 660 has recently undergone a spectacular radio outburst; using a combination of archival radio and Chandra X-ray data, together with new observations, the nature of this event is investigated. Radio observations made using e-MERLIN in mid-2013 show a new compact and extremely bright continuum source at the centre of the galaxy. High angular resolution observations carried out with the European VLBI Network show an obvious jet-like feature to the north east and evidence of a weak extension to the west, possibly a counter-jet. We also examine high angular resolution Hi spectra of these new sources, and the radio spectral energy distribution using the new wide-band capabilities of e-MERLIN. We compare the properties of the new object with possible explanations, concluding that we are seeing a period of new AGN activity in the core of this polar ring galaxy.

Section: A Polar Ring Galaxymentioning

confidence: 99%

A new period of activity in the core of NGC 660

Argo

Bemmel

Connolly

et al. 2015

“…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

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.

“…McGaugh et al 2000;Bell & de Jong 2001;Gurovich et al 2004;McGaugh 2005;Pfenniger & Revaz 2005;Begum et al 2008;Trachternach et al 2009;Stark et al 2009;Gurovich et al 2010;Zaritsky et al 2014), extension of the Tully-Fisher relation (hereafter TF, e.g. Tully & Fisher 1977;Pierce & Tully 1988;Teerikorpi 1995;Giovanelli et al 1997b;Courteau & Rix 1999;Tully & Pierce 2000;Giovanelli et al 1997a;Karachentsev et al 2002;Bedregal et al 2006;Noordermeer & Verheijen 2007;Springob et al 2007;Williams et al 2010;Tully & Courtois 2012;Mocz et al 2012;Rawle et al 2013;Torres-Flores et al 2013;Sorce et al 2013Sorce et al , 2014b to the low luminosity galaxies, is often used to constrain and test galaxy formation and evolution models, with various computational methods, in the ΛCDM scenario as well as in alternative theories (e.g. Steinmetz & Navarro 1999;Mo et al 1998;McGaugh & de Blok 1998;Eisenstein & Loeb 1995;van den Bosch 2000;Mayer & Moore 2004;Gnedin et al 2007;Governato et al 2007;Avila-Reese et al 2008;McGaugh 2012;…”

Section: Introductionmentioning

confidence: 99%

The baryonic Tully–Fisher relation cares about the galaxy sample

Sorce¹,

Guo²

2016

The Baryonic Tully-Fisher relation (BTFR) is a clear manifestation of the underlying physics of galaxy formation. As such, it is used to constrain and test galaxy formation and evolution models. Of particular interest, apart from the slope of the relation, is its intrinsic scatter. In this paper, we use the eagle simulation to study the dependence of the BTFR on the size of the simulated galaxy sample. The huge number of datapoint available in the simulation is indeed not available with current observations. Observational studies that computed the BTFR used various (small) size samples with the only obligation to have galaxies spanning over a large range of masses and rotation rates. Accordingly, to compare observational and theoretical results, we build a large number of various size datasets using the same criterion and derive the BTFR for all of them. Unmistakably, their is an effect of the number of galaxies used to derive the relation. The smaller the number, the larger the standard deviation around the average slope and intrinsic scatter of a given size sample of galaxies. This observation allows us to alleviate the tensions between observational measurements and ΛCDM predictions. Namely, the size of the observational samples adds up to the complexity in comparing observed and simulated relations to discredit or confirm ΛCDM. Similarly, samples, even large, that do not reflect the galaxy distribution give on average biased results. Large size samples reproducing the underlying distribution of galaxies constitute a supplementary necessity to compare efficiently observations and simulations.