scholarly journals Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE). XI. Two dimensional Halpha kinematics of the edge-on ram pressure stripped galaxy NGC4330

2022 ◽  
Author(s):  
M. M. Sardaneta ◽  
P. Amram ◽  
A. Boselli ◽  
B. Vollmer ◽  
M. Rosado ◽  
...  
Keyword(s):  
Two Dimensional ◽  
Gas Emission ◽  
Environmental Survey ◽  
Ram Pressure

scholarly journals A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE)

2020 ◽  
Vol 644 ◽  
pp. A161
Author(s):  
A. Longobardi ◽  
A. Boselli ◽  
M. Fossati ◽  
J. A. Villa-Vélez ◽  
S. Bianchi ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Main Body ◽  
Mass Ratio ◽  
Gas Emission ◽  
Environmental Survey ◽  
Ram Pressure ◽  
Mass Ratios ◽  
The Galaxy ◽  
Atomic Gas ◽  
The One

Aims. We measure far-infrared (FIR) emission from tails of stripped dust following the ionised and atomic gas components in galaxies undergoing ram pressure stripping. We study the dust-to-gas relative distribution and mass ratio in the stripped interstellar medium and relate them to those of the intra-cluster medium (ICM), thus linking the cluster-ICM-galaxy evolution at small-scales. The galaxy sample consists of three Scd Virgo galaxies with stellar masses in the range of 109 ≲ M* ≲ 1010 M⊙ and within 1 Mpc from the cluster centre, namely NGC 4330, NGC 4522, and NGC 4654. Methods. Through the analysis of Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE) Hα, Herschel SPIRE FIR, and VLA Imaging of Virgo in Atomic gas HI data, we trace the spatial distribution of the tails and infer the dust and gas masses from the measured FIR 250 μm and HI flux densities. Dust-to-gas mass ratios in the tails are analysed as a function of the galaxy mass, metallicity, and dust temperature. Results. Along the stripped component, the dust distribution closely follows the HI and Hα emitting gas, which extend beyond the optical disc (defined by the B-band 25th magnitude isophote). In these regions, the dust-to-gas mass ratios are 2.0 ± 0.6 × 10−3, 0.7 ± 0.1 × 10−3, and 0.4 ± 0.03 × 10−3 for NGC 4330, NGC 4522, and NGC 4654, respectively. Thus, dust is widespread in the stripped material with a lower dust-to-gas mass ratio (up to a factor of 15) than the one measured in the main body of nearby galaxies. We also find a negative trend in the dust-to-gas mass ratio as a function of the metallicity that can be explained in terms of a dust component more centrally concentrated in more metal-rich systems. Together with the finding that the stripped dust is cold, Td ≲ 25 K, our results can be interpreted as a consequence of an outside-in stripping of the galaxy interstellar medium. Conclusions. Gas and dust in galaxies are perturbed in a similar fashion by the cluster environment, although their relative contribution differs from the one measured in the main body of the galaxies. When this value is considered, ram pressure stripping is consistent with being one of the key mechanisms in building up the Virgo intra-cluster component, injecting dust grains into the ICM, thus contributing to its metal enrichment.

scholarly journals A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE)

2020 ◽  
Vol 634 ◽  
pp. L1 ◽  
Author(s):  
A. Boselli ◽  
M. Fossati ◽  
A. Longobardi ◽  
S. Boissier ◽  
M. Boquien ◽  
...  
Keyword(s):  
Star Formation ◽  
Hii Regions ◽  
Morphological Type ◽  
Stellar Mass ◽  
Virgo Cluster ◽  
Gas Emission ◽  
Environmental Survey ◽  
Star Formation Activity ◽  
Wide Range ◽  
The Impact

The Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE) is a blind narrow-band Hα + [NII] imaging survey of the Virgo cluster carried out with MegaCam at the Canada-French-Hawaii telescope. We use a new set of data extracted from VESTIGE to study the impact of the hostile cluster environment on the star formation process down to the scale of HII regions (∼50 pc). Here, HII regions are identified and their parameters measured using the HIIPHOT code on a sample of 114 late-type galaxies spanning a wide range in morphological type (Sa-Sd, Im, BCD), stellar mass (106.5 ≤ Mstar ≤ 1011 M⊙), and star formation activity (10−3 ≤ SFR ≤ 10 M⊙ yr−1). Owing to the exquisite average resolution of the VESTIGE data (0.65 arcsec), we detect 11302 HII regions with an Hα luminosity L(Hα) ≥ 1037 erg s−1. We show that the typical number of HII regions in gas-stripped objects is significantly lower than in healthy late-types of similar stellar mass. We also show that in these gas-stripped galaxies the number of HII regions significantly drops outside the effective radius, suggesting that the quenching process occurs outside-in, in agreement with other multifrequency observations. These new results consistently confirm that the main mechanism responsible for the decrease of the star formation activity observed in cluster galaxies is ram pressure, allowing us to discard other milder processes such as starvation or strangulation, which are unable to reproduce the observed radially truncated profiles.

scholarly journals A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE)

2018 ◽  
Vol 620 ◽  
pp. A164 ◽  
Author(s):  
A. Boselli ◽  
M. Fossati ◽  
G. Consolandi ◽  
P. Amram ◽  
C. Ge ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Narrow Band ◽  
Virgo Cluster ◽  
X Rays ◽  
Environmental Survey ◽  
North West ◽  
The North ◽  
Ram Pressure ◽  
The Galaxy

We observed the late-type peculiar galaxy NGC 4424 during the Virgo Environmental Survey Tracing Galaxy Evolution (VESTIGE), a blind narrow-band Hα+[NII] imaging survey of the Virgo cluster carried out with MegaCam at the Canada-French-Hawaii Telescope (CFHT). The presence of a ∼110 kpc (in projected distance) HI tail in the southern direction indicates that this galaxy is undergoing a ram pressure stripping event. The deep narrow-band image revealed a low surface brightness (Σ(Hα) ≃ 4 × 10−18 erg s−1 cm−2 arcsec−2) ionised gas tail ∼10 kpc in length extending from the centre of the galaxy to the north-west, thus in the direction opposite to the HI tail. Chandra and XMM X-rays data do not show a compact source in the nucleus or an extended tail of hot gas, while IFU spectroscopy (MUSE) indicates that the gas is photo-ionised in the inner regions and shock-ionised in the outer parts. Medium-resolution (MUSE) and high-resolution (Fabry-Perot) IFU spectroscopy confirms that the ionised gas is kinematically decoupled from the stellar component and indicates the presence of two kinematically distinct structures in the stellar disc. The analysis of the SED of the galaxy indicates that the activity of star formation was totally quenched in the outer disc ∼250–280 Myr ago, while only reduced by ∼80% in the central regions. All this observational evidence suggests that NGC 4424 is the remnant of an unequal-mass merger that occurred ≲500 Myr ago when the galaxy was already a member of the Virgo cluster, and is now undergoing a ram pressure stripping event that has removed the gas and quenched the activity of star formation in the outer disc. The tail of ionised gas probably results from the outflow produced by a central starburst fed by the collapse of gas induced by the merging episode. This outflow is sufficiently powerful to overcome the ram pressure induced by the intracluster medium on the disc of the galaxy crossing the cluster. This analysis thus suggests that feedback can participate in the quenching process of galaxies in high-density regions.

scholarly journals A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE)

2018 ◽  
Vol 614 ◽  
pp. A57 ◽  
Author(s):  
M. Fossati ◽  
J. T. Mendel ◽  
A. Boselli ◽  
J. C. Cuillandre ◽  
B. Vollmer ◽  
...  
Keyword(s):  
Major Axis ◽  
Virgo Cluster ◽  
Monte Carlo Code ◽  
Gas Stripping ◽  
Gas Emission ◽  
Filamentary Structure ◽  
Environmental Survey ◽  
Star Forming ◽  
Very Large Telescope ◽  
The Galaxy

The Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE) is a blind narrow-band Hα + [NII] imaging survey carried out with MegaCam at the Canada-France-Hawaii Telescope. During pilot observations taken in the spring of 2016 we observed NGC 4330, an intermediate mass (M* ≃ 109.8 M⊙) edge-on star forming spiral currently falling into the core of the Virgo cluster. While previous Hα observations showed a clumpy complex of ionised gas knots outside the galaxy disc, new deep observations revealed a low surface brightness ~10 kpc tail exhibiting a peculiar filamentary structure. The filaments are remarkably parallel to one another and clearly indicate the direction of motion of the galaxy in the Virgo potential. Motivated by the detection of these features which indicate ongoing gas stripping, we collected literature photometry in 15 bands from the far-UV to the far-IR and deep optical long-slit spectroscopy using the FORS2 instrument at the ESO Very Large Telescope. Using a newly developed Monte Carlo code that jointly fits spectroscopy and photometry, we reconstructed the star formation histories in apertures along the major axis of the galaxy. Our results have been validated against the output of CIGALE, a fitting code which has been previously used for similar studies. We found a clear outside-in gradient with radius of the time when the quenching event started: the outermost radii were stripped ~500 Myr ago, while the stripping reached the inner 5 kpc from the centre in the last 100 Myr. Regions at even smaller radii are currently still forming stars fueled by the presence of HI and H2 gas. When compared to statistical studies of the quenching timescales in the local Universe we find that ram pressure stripping of the cold gas is an effective mechanism to reduce the transformation times for galaxies falling into massive clusters. Future systematic studies of all the active galaxies observed by VESTIGE in the Virgo cluster will extend these results to a robust statistical framework.

Paper 15: Solutions for Flow in a Bearing Groove

1967 ◽  
Vol 182 (14) ◽  
pp. 120-131
Author(s):  
C. Ettles
Keyword(s):  
Nusselt Number ◽  
Stokes Equations ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Uniform Mesh ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Ram Pressure ◽  
Carry Over ◽  
Varying Viscosity

The flow regime in a transverse feed groove is considered and various assumptions to make the problem amenable to theoretical analysis are discussed. A finite-difference method for solving the varying viscosity, two-dimensional Navier–Stokes equations is described. A non-uniform mesh is used and dissipation is taken into account. The flow is assumed to be laminar. Solutions are given for flow in square and rectangular grooves for efflux Reynolds numbers in the range 1–50. Values are given for circulation flow, hot oil carry-over, friction, ram pressure and Nusselt number. It is suggested that the Nusselt number for flow in a transverse groove has a constant characteristic value which could be of value to designers once firmly established.

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