The host galaxy of GRB 980425 / SN1998bw: a collisional ring galaxy. (arXiv:1903.00485v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Arabsalmani_M/0/1/0/all/0/1">M. Arabsalmani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Roychowdhury_S/0/1/0/all/0/1">S. Roychowdhury</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Starkenburg_T/0/1/0/all/0/1">T. K. Starkenburg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Christensen_L/0/1/0/all/0/1">L. Christensen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Floch_E/0/1/0/all/0/1">E. Le Floc'h</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kanekar_N/0/1/0/all/0/1">N. Kanekar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bournaud_F/0/1/0/all/0/1">F. Bournaud</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zwaan_M/0/1/0/all/0/1">M. A. Zwaan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fynbo_J/0/1/0/all/0/1">J. P. U. Fynbo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moller_P/0/1/0/all/0/1">P. Møller</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pian_E/0/1/0/all/0/1">E. Pian</a>
We report Giant Metrewave Radio Telescope (GMRT) , Very Large Telescope (VLT)
and Spitzer Space Telescope observations of ESO 184$-$G82, the host galaxy of
GRB 980425/SN 1998bw, that yield evidence of a companion dwarf galaxy at a
projected distance of 13 kpc. The companion, hereafter GALJ193510-524947, is a
gas-rich, star-forming galaxy with a star formation rate of
$rm0.004,M_{odot}, yr^{-1}$, a gas mass of $10^{7.1pm0.1} M_{odot}$, and
a stellar mass of $10^{7.0pm0.3} M_{odot}$. The interaction between ESO
184$-$G82 and GALJ193510-524947 is evident from the extended gaseous structure
between the two galaxies in the GMRT HI 21 cm map. We find a ring of high
column density HI gas, passing through the actively star forming regions of ESO
184$-$G82 and the GRB location. This ring lends support to the picture in which
ESO 184$-$G82 is interacting with GALJ193510-524947. The massive stars in
GALJ193510-524947 have similar ages to those in star-forming regions in ESO
184$-$G82, also suggesting that the interaction may have triggered star
formation in both galaxies. The gas and star formation properties of ESO
184$-$G82 favour a head-on collision with GALJ193510-524947 rather than a
classical tidal interaction. We perform state-of-the art simulations of
dwarf–dwarf mergers and confirm that the observed properties of ESO 184$-$G82
can be reproduced by collision with a small companion galaxy. This is a very
clear case of interaction in a gamma ray burst host galaxy, and of
interaction-driven star formation giving rise to a gamma ray burst in a dense
environment.
We report Giant Metrewave Radio Telescope (GMRT) , Very Large Telescope (VLT)
and Spitzer Space Telescope observations of ESO 184$-$G82, the host galaxy of
GRB 980425/SN 1998bw, that yield evidence of a companion dwarf galaxy at a
projected distance of 13 kpc. The companion, hereafter GALJ193510-524947, is a
gas-rich, star-forming galaxy with a star formation rate of
$rm0.004,M_{odot}, yr^{-1}$, a gas mass of $10^{7.1pm0.1} M_{odot}$, and
a stellar mass of $10^{7.0pm0.3} M_{odot}$. The interaction between ESO
184$-$G82 and GALJ193510-524947 is evident from the extended gaseous structure
between the two galaxies in the GMRT HI 21 cm map. We find a ring of high
column density HI gas, passing through the actively star forming regions of ESO
184$-$G82 and the GRB location. This ring lends support to the picture in which
ESO 184$-$G82 is interacting with GALJ193510-524947. The massive stars in
GALJ193510-524947 have similar ages to those in star-forming regions in ESO
184$-$G82, also suggesting that the interaction may have triggered star
formation in both galaxies. The gas and star formation properties of ESO
184$-$G82 favour a head-on collision with GALJ193510-524947 rather than a
classical tidal interaction. We perform state-of-the art simulations of
dwarf–dwarf mergers and confirm that the observed properties of ESO 184$-$G82
can be reproduced by collision with a small companion galaxy. This is a very
clear case of interaction in a gamma ray burst host galaxy, and of
interaction-driven star formation giving rise to a gamma ray burst in a dense
environment.
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