Hot gas in Mach cones around Virgo cluster spiral galaxies

Weżgowiec, M.; Vollmer, B.; Ehle, M.; Dettmar, R.‐J.; Bomans, D. J.; Chyży, K. T.; Urbanik, M.; Soida, M.

doi:10.1051/0004-6361/201016344

Cited by 21 publications

(37 citation statements)

References 46 publications

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“…The asymmetry of the polarized intensity, which has a higher polarization degree in the south and apparent polarization B-vectors aligned in the southeast-northwest direction, suggest that the galaxy is moving in the southwestern direction, as concluded by Yoshida et al (2004) from the Hα outflow alignments and their spectral analysis. This also seems to be confirmed by the X-ray data presented by Weżgowiec et al (2011), who detected an extended hot gas tail corresponding to a long H i tail found by Oosterloo & van Gorkom (2005).…”

Section: Asymmetric Halo In Edge-on Galaxiessupporting

confidence: 75%

“…We also carry out X-ray studies of the Virgo cluster galaxies, the results of which will place tight constraints on the nature of the interactions of galaxies with the intracluster medium (ICM). Our first results were published in Weżgowiec et al (2011), where we report the first detection of a hot gas halo around a Virgo cluster galaxy reminiscent of a Mach cone geometry. The thorough analysis of X-ray data from selected Virgo cluster galaxies will be presented in separate papers.…”

Section: Introductionmentioning

confidence: 98%

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The magnetic fields of large Virgo cluster spirals. II

Weżgowiec

Urbanik

Beck

et al. 2012

A&A

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Context. The Virgo cluster of galaxies provides excellent conditions for studying interactions of galaxies with the cluster environment. Both the high-velocity tidal interactions and effects of ram pressure stripping by the intracluster gas can be investigated in detail. Aims. We extend our systematic search for possible anomalies in the magnetic field structures of Virgo cluster spirals in order to characterize a variety of effects and attribute them to different disturbing agents. Methods. Six angularly large Virgo cluster spiral galaxies (NGC 4192, NGC 4302, NGC 4303, NGC 4321, NGC 4388, and NGC 4535) were targets of a sensitive total power and polarization study using the 100-m radio telescope in Effelsberg at 4.85 GHz and 8.35 GHz (except for NGC 4388 observed only at 4.85 GHz, and NGC 4535 observed only at 8.35 GHz). The presented twofrequency studies allow Faraday rotation analysis. Results. Magnetic field structures distorted to various extent are found in all galaxies. Three galaxies (NGC 4302, NGC 4303, and NGC 4321) show some signs of possible tidal interactions, while NGC 4388 and NGC 4535 have very likely experienced strong ram-pressure and shearing effects, respectively, visible as distortions and asymmetries of polarized intensity distributions. As in our previous study, even strongly perturbed galaxies closely follow the radio-far-infrared correlation. In NGC 4303 and NGC 4321, we observe symmetric spiral patterns of the magnetic field and in NGC 4535 an asymmetric pattern. Conclusions. The cluster environment clearly affects the evolution of its member galaxies via various effects. Magnetic fields allow us to trace even weak interactions that are difficult to detect with other observations. Our results show that the degree of distortions of a galaxy is not a simple function of the distance to the cluster center but reflects also the history of its interactions. The angle Θ between the velocity vector u and the rotation vector Ω of a galaxy may be a general parameter that describes the level of distortions of galactic magnetic fields. Information about the motions of galaxies in the sky plane and their three-dimensional distribution, as well as information about the intracluster medium can also be obtained from the Faraday rotation analysis.

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Section: Asymmetric Halo In Edge-on Galaxiessupporting

confidence: 75%

Section: Introductionmentioning

confidence: 98%

The magnetic fields of large Virgo cluster spirals. II

Weżgowiec

Urbanik

Beck

et al. 2012

A&A

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“…The known X-ray tails have T ICM /T tail ratios of 3 − 8 (Sun & Vikhlinin 2005;Sun et al 2010;Weżgowiec et al 2011). If we simply take this range for the ratio, the expected tail temperature of IC3418 is 0.3 − 0.8 keV, for a surrounding ICM temperature of ∼ 2.5 keV (Shibata et al 2001).…”

Section: Results -Chandramentioning

confidence: 99%

Search for cold and hot gas in the ram pressure stripped Virgo dwarf galaxy IC 3418

Jáchym¹,

Kenney²,

Růžička³

et al. 2013

A&A

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We present IRAM 30m sensitive upper limits on CO emission in the ram pressure stripped dwarf Virgo galaxy IC3418 and in a few positions covering H ii regions in its prominent 17 kpc UV/Hα gas-stripped tail. In the central few arcseconds of the galaxy, we report a possible marginal detection of about 1 × 10 6 M ⊙ of molecular gas (assuming a Galactic CO-to-H 2 conversion factor) that could correspond to a surviving nuclear gas reservoir. We estimate that there is less molecular gas in the main body of IC3418, by at least a factor of 20, than would be expected from the pre-quenching UV-based star formation rate assuming the typical gas depletion timescale of 2 Gyr. Given the lack of star formation in the main body, we think the H 2 -deficiency is real, although some of it may also arise from a higher CO-to-H 2 factor typical in low-metallicity, low-mass galaxies. The presence of H ii regions in the tail of IC3418 suggests that there must be some dense gas; however, only upper limits of < 1 × 10 6 M ⊙ were found in the three observed points in the outer tail. This yields an upper limit on the molecular gas content of the whole tail < 1 × 10 7 M ⊙ , which is an amount similar to the estimates from the observed star formation rate over the tail. We also present strong upper limits on the X-ray emission of the stripped gas in IC3418 from a new Chandra observation. The measured X-ray luminosity of the IC3418 tail is about 280 times lower than that of ESO 137-001, a spiral galaxy in a more distant cluster with a prominent ram pressure stripped tail. Non-detection of any diffuse X-ray emission in the IC3418 tail may be due to a low gas content in the tail associated with its advanced evolutionary state and/or due to a rather low thermal pressure of the surrounding intra-cluster medium.

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“…This means that we observe this galaxy after the end of the starburst phase, whose effects are now diminishing. This scenario would also explain the significant strength of the magnetic field of NGC 4569 (Weżgowiec 2009;Chyży et al, in prep. ), which is quite surprising for an anaemic galaxy.…”

Section: Past Starburst In Ngc 4569mentioning

confidence: 97%

“…paper discussing observational evidence of Mach cones around Virgo cluster galaxies (Weżgowiec et al 2011). Analyses of radio data for NGC 4254 (Chyży et al 2007 andChyży 2008) and NGC 4569 (Chyży et al, in prep.…”

Section: Introductionmentioning

confidence: 99%

Tidal interaction vs. ram pressure stripping effects as seen in X-rays

Weżgowiec

Bomans

Ehle

et al. 2012

A&A

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Context. Cluster and group spiral galaxies are very often affected by their environment. The hot intracluster/intragroup medium (ICM/IGM) and a high galaxy density can lead to perturbations of the galactic interstellar medium (ISM) due to ram pressure and/or tidal interaction effects. In radio polarimetry observations, both phenomena may manifest similar features. X-ray data can help to determine the real origin of the perturbation. Aims. We analyse the distribution and physical properties of the hot gas in the Virgo cluster spiral galaxies NGC 4254 and NGC 4569, which indicate that the cluster environment has had a significant influence on their properties. By performing both spatial and spectral analyses of X-ray data, we try to distinguish between two major phenomena: tidal and ram pressure interactions. We compare our findings with the case of NGC 2276, in which a shock was reported, by analysing XMM-Newton X-ray data for this galaxy. Methods. We use archival XMM-Newton observations of NGC 4254, NGC 4569, and NGC 2276. Maps of the soft diffuse emission in the energy band 0.2−1 keV are obtained. For the three galaxies, especially at the position of magnetic field enhancements we perform a spectral analysis to derive gas temperatures and thus to look for shock signatures. A shock is a signature of ram pressure resulting from supersonic velocities; weak tidal interactions are not expected to influence the temperature of the ionized gas. Results. In NGC 4254, we do not observe any temperature increase at the position of the bright polarized radio ridge. This suggests that the feature is formed by tidal interactions, and not by ram pressure stripping. NGC 4569 shows a higher temperature at the position of the polarized features, which may be indicative of ram-pressure effects. For NGC 2276, we do not find clear indications of a shock. Although ram-pressure effects seem to be visible, the main driver of the observed distortions is most likely tidal interaction. Conclusions. Determining gas temperatures via sensitive X-ray observations at the position of polarized radio ridges seems to be a good method for distinguishing between ram pressure and tidal interaction effects acting upon a galaxy.

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Hot gas in Mach cones around Virgo cluster spiral galaxies

Cited by 21 publications

References 46 publications

The magnetic fields of large Virgo cluster spirals. II

The magnetic fields of large Virgo cluster spirals. II

Search for cold and hot gas in the ram pressure stripped Virgo dwarf galaxy IC 3418

Tidal interaction vs. ram pressure stripping effects as seen in X-rays

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