Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: SN 2017ein and the Possible First Identification of a Type Ic Supernova
  Progenitor   We have identified a progenitor candidate in archival Hubble Space Telescope
(HST) images for the Type Ic SN 2017ein in NGC 3938, pinpointing the
candidate's location via HST Target-of-Opportunity imaging of the SN itself.
This would be the first identification of a stellar-like object as a progenitor
candidate for any Type Ic supernova to date. We also present observations of SN
2017ein during the first ~49 days since explosion. We find that SN 2017ein most
resembles the well-studied Type Ic SN 2007gr. We infer that SN 2017ein
experienced a total visual extinction of A_V~1.0--1.9 mag, predominantly
because of dust within the host galaxy. Although the distance is not well
known, if this object is the progenitor, it was likely of high initial mass,
~47--48 M_sun if a single star, or ~60--80 M_sun if in a binary system.
However, we also find that the progenitor candidate could be a very blue and
young compact cluster, further implying a very massive (>65 M_sun) progenitor.
Furthermore, the actual progenitor might not be associated with the candidate
at all and could be far less massive. From the immediate stellar environment,
we find possible evidence for three different populations; if the SN progenitor
was a member of the youngest population, this would be consistent with an
initial mass of ~57 M_sun. After it has faded, the SN should be reobserved at
high spatial resolution and sensitivity, to determine whether the candidate is
indeed the progenitor.

10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
35
The categories of this paper are: mtrl-th