An Unambiguous Separation of Gamma-Ray Bursts into Two Classes from Prompt Emission Alone. (arXiv:2005.13554v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Jespersen_C/0/1/0/all/0/1">Christian K. Jespersen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Severin_J/0/1/0/all/0/1">Johann B. Severin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Steinhardt_C/0/1/0/all/0/1">Charles L. Steinhardt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vinther_J/0/1/0/all/0/1">Jonas Vinther</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fynbo_J/0/1/0/all/0/1">Johan P. U. Fynbo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Selsing_J/0/1/0/all/0/1">Jonatan Selsing</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Watson_D/0/1/0/all/0/1">Darach Watson</a>
The duration of a gamma-ray burst (GRB) is a key indicator of its physics
origin, with long bursts perhaps associated with the collapse of massive stars
and short bursts with mergers of neutron stars.However, there is substantial
overlap in the properties of both short and long GRBs and neither duration nor
any other parameter so far considered completely separates the two groups. Here
we unambiguously classify every GRB using a machine-learning,
dimensionality-reduction algorithm, t-distributed stochastic neighborhood
embedding (t-SNE), providing a catalog separating all Swift GRBs into two
groups. Although the classification takes place only using prompt emission
light curves,every burst with an associated supernova is found in the longer
group and bursts with kilonovae in the short, suggesting along with the
duration distributions that these two groups are truly long and short GRBs. Two
bursts with a clear absence of a supernova belong to the longer class,
indicating that these might have been direct-collapse black holes, a proposed
phenomenon that may occur in the deaths of more massive stars.
The duration of a gamma-ray burst (GRB) is a key indicator of its physics
origin, with long bursts perhaps associated with the collapse of massive stars
and short bursts with mergers of neutron stars.However, there is substantial
overlap in the properties of both short and long GRBs and neither duration nor
any other parameter so far considered completely separates the two groups. Here
we unambiguously classify every GRB using a machine-learning,
dimensionality-reduction algorithm, t-distributed stochastic neighborhood
embedding (t-SNE), providing a catalog separating all Swift GRBs into two
groups. Although the classification takes place only using prompt emission
light curves,every burst with an associated supernova is found in the longer
group and bursts with kilonovae in the short, suggesting along with the
duration distributions that these two groups are truly long and short GRBs. Two
bursts with a clear absence of a supernova belong to the longer class,
indicating that these might have been direct-collapse black holes, a proposed
phenomenon that may occur in the deaths of more massive stars.
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