J/A+A/646/A139 IC 3476 Halpha image (Boselli+, 2021)
A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE).
IX. The effects of ram pressure stripping down to the scale of individual HII
regions in the dwarf galaxy IC 3476
Boselli A., Lupi A., Epinat B., Amram P., Fossati M., Anderson J.P.,
Boissier S., Boquien M., Consolandi G., Cote P., Cuillandre J.C.,
Ferrarese L., Galbany L., Gavazzi G., Gomez-Lopez J.A., Gwyn S., Hensler G.,
Hutchings J., Kuncarayakti H., Longobardi A., Peng E.W., Plana H.,
Postma J., Roediger J., Roehlly Y., Schimd C., Trinchieri G., Vollmer B.
<Astron. Astrophys. 646, A139 (2021)>
=2021A&A...646A.139B 2021A&A...646A.139B (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Interstellar medium ; Radio lines
Keywords: galaxies: clusters: general - galaxies: clusters: individual: Virgo -
galaxies: evolution - galaxies: interactions - galaxies: ISM
Abstract:
We study the IB(s)m galaxy IC 3476 observed in the context of the
Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE), a
blind narrow-band Hα+[NII] imaging survey of the Virgo cluster
carried out with MegaCam at the CFHT. The deep narrow-band image
reveals a very pertubed ionised gas distribution that is characterised
by a prominent banana-shaped structure in the front of the galaxy
formed of giant HII regions crossing the stellar disc. Star-forming
structures, at ∼8kpc from the edges of the stellar disc, are also
detected in a deep far-ultraviolet ASTROSAT/UVIT image. This
particular morphology indicates that the galaxy is undergoing an
almost edge-on ram pressure stripping event. The same Hα+[NII]
image also shows that the star formation activity is totally quenched
in the leading edge of the disc, where the gas has been removed during
the interaction with the surrounding medium. The spectral energy
distribution fitting analysis of the multi-frequency data indicates
that this quenching episode is very recent (∼50Myr), and roughly
corresponds to an increase of the star formation activity by a factor
of ∼161% in the inner regions with respect to that expected for
secular evolution. The analysis of these data, whose angular
resolution enables the study of the induced effects of the
perturbation down to the scale of individual HII regions
(req~=40pc), also suggests that the increase of star formation
activity is due to the compression of the gas along the stellar disc
of the galaxy, which is able to increase its mean electron density and
boost the star formation process producing bright HII regions with
luminosities up to L(Hα)~=1038erg/s. The combined analysis of
the VESTIGE data with deep IFU spectroscopy gathered with MUSE and
with high spectral resolution Fabry Perot data also indicates that the
hydrodynamic interaction has deeply perturbed the velocity field of
the ionised gas component while leaving that of the stellar disc
unaffected. The comparison of the data with tuned high-resolution
hydrodynamic simulations accounting for the different gas phases
(atomic, molecular, ionised) consistently indicates that the
perturbing event is very recent (50-150Myr), once again confirming
that ram pressure stripping is a violent phenomenon that is able to
perturb the evolution of galaxies in rich environments on short
timescales.
Description:
Halpha narrow-band continuum subtracted image (in fits format) of the
galaxy IC 3476, used to produce Fig. 1 of the paper.
Objects:
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RA (2000) DE Designation(s)
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12 32 41.74 +14 03 05.8 IC 3476 = LEDA 41608
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 131 1 Information of fits image
fits/* . 1 fits image
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 24 F5.3 arcsec/pix scale Scale of the image
26- 29 I4 --- Nx Number of pixels along X-axis
31- 34 I4 --- Ny Number of pixels along Y-axis
36- 39 I4 Kibyte size Size of FITS file
41- 63 A23 --- FileName Name of FITS file, in subdirectory fits
65-131 A67 --- Title Title of the FITS file
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Acknowledgements:
Alessadro Boselli, alessandro.boselli(at)lam.fr
References:
Boselli et al., Paper I 2018A&A...614A..56B 2018A&A...614A..56B
Fossati et al., Paper II 2018A&A...614A..57F 2018A&A...614A..57F
Boselli et al., Paper III 2018A&A...615A.114B 2018A&A...615A.114B
Boselli et al., Paper IV 2018A&A...620A.164B 2018A&A...620A.164B
Boselli et al., Paper V 2019A&A...623A..52B 2019A&A...623A..52B
Boselli et al., Paper VI 2020A&A...634L...1B 2020A&A...634L...1B
(End) Patricia Vannier [CDS] 25-Dec-2020