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The Cow:Discovery of a Luminous, Hot, and Rapidly Evolving Transient

Authors :
Prentice, S. J.
Maguire, K.
Smartt, S. J.
Magee, M. R.
Schady, P.
Sim, S.
Chen, T. -W.
Clark, P.
Colin, C.
Fulton, M.
McBrien, O.
O`Neill, D.
Smith, K. W.
Ashall, C.
Chambers, K. C.
Denneau, L.
Flewelling, H. A.
Heinze, A.
Holoien, T. W. -S.
Huber, M. E.
Kochanek, C. S.
Mazzali, P. A.
Prieto, J. L.
Rest, A.
Shappee, B. J.
Stalder, B.
Stanek, K. Z.
Stritzinger, M. D.
Thompson, T. A.
Tonry, J. L.
Université Pierre et Marie Curie - Paris 6 (UPMC)
Source :
Prentice, S J, Maguire, K, Smartt, S J, Magee, M R, Schady, P, Sim, S, Chen, T-W, Clark, P, Colin, C, Fulton, M, McBrien, O, O'Neill, D, Smith, K W, Ashall, C, Chambers, K C, Denneau, L, Flewelling, H A, Heinze, A, Holoien, T W-S, Huber, M E, Kochanek, C S, Mazzali, P A, Prieto, J L, Rest, A, Shappee, B J, Stalder, B, Stanek, K Z, Stritzinger, M D, Thompson, T A & Tonry, J L 2018, ' The Cow : Discovery of a Luminous, Hot, and Rapidly Evolving Transient ', Astrophysical Journal Letters, vol. 865, no. 1, 3 . https://doi.org/10.3847/2041-8213/aadd90, Prentice, S, Maguire, K, Smartt, S, Magee, M, Schady, P, Sim, S, Chen, T-W, Clark, P, Colin, C, Fulton, M, McBrien, O, O'Neill, D, Smith, K, Ashall, C, Chambers, K C, Denneau, L, Flewelling, H A, Heinze, A, Holoien, T W-S, Huber, M E, Kochanek, C S, Mazzali, P A, Prieto, J L, Rest, A, Shappee, B J, Stalder, B, Stanek, K Z, Stritzinger, M D, Thompson, T A & Tonry, J L 2018, ' The Cow: Discovery of a Luminous, Hot, and Rapidly Evolving Transient ', The Astrophysical Journal Letters, vol. 865, no. L3, pp. 1-8 . https://doi.org/10.3847/2041-8213/aadd90, Astrophys.J., Astrophys.J., 2018, 865 (1), pp.L3. ⟨10.3847/2041-8213/aadd90⟩, The Astrophysical Journal, Astrophys.J.Lett., Astrophys.J.Lett., 2018, 865 (1), pp.L3. ⟨10.3847/2041-8213/aadd90⟩
Publication Year :
2018

Abstract

We present the ATLAS discovery and initial analysis of the first 18 days of the unusual transient event, ATLAS18qqn/AT2018cow. It is characterized by a high peak luminosity ($\sim$1.7 $\times$ 10$^{44}$ erg s$^{-1}$), rapidly evolving light curves ($>$5 mag rise to peak in $\sim$3.5 days), and hot blackbody spectra, peaking at $\sim$27000 K that are relatively featureless and unchanging over the first two weeks. The bolometric light curve cannot be powered by radioactive decay under realistic assumptions. The detection of high-energy emission may suggest a central engine as the powering source. Using a magnetar model, we estimated an ejected mass of $0.1-0.4$ \msol, which lies between that of low-energy core-collapse events and the kilonova, AT2017gfo. The spectra cooled rapidly from 27000 to 15000 K in just over 2 weeks but remained smooth and featureless. Broad and shallow emission lines appear after about 20 days, and we tentatively identify them as He I although they would be redshifted from their rest wavelengths. We rule out that there are any features in the spectra due to intermediate mass elements up to and including the Fe-group. The presence of r-process elements cannot be ruled out. If these lines are due to He, then we suggest a low-mass star with residual He as a potential progenitor. Alternatively, models of magnetars formed in neutron-star mergers give plausible matches to the data.<br />Accepted for publication in ApJL, updated to reflect the published version

Details

Language :
English
ISSN :
0004637X, 00670049, 15383873, 15383881, and 20418205
Database :
OpenAIRE
Journal :
Prentice, S J, Maguire, K, Smartt, S J, Magee, M R, Schady, P, Sim, S, Chen, T-W, Clark, P, Colin, C, Fulton, M, McBrien, O, O'Neill, D, Smith, K W, Ashall, C, Chambers, K C, Denneau, L, Flewelling, H A, Heinze, A, Holoien, T W-S, Huber, M E, Kochanek, C S, Mazzali, P A, Prieto, J L, Rest, A, Shappee, B J, Stalder, B, Stanek, K Z, Stritzinger, M D, Thompson, T A & Tonry, J L 2018, ' The Cow : Discovery of a Luminous, Hot, and Rapidly Evolving Transient ', Astrophysical Journal Letters, vol. 865, no. 1, 3 . https://doi.org/10.3847/2041-8213/aadd90, Prentice, S, Maguire, K, Smartt, S, Magee, M, Schady, P, Sim, S, Chen, T-W, Clark, P, Colin, C, Fulton, M, McBrien, O, O'Neill, D, Smith, K, Ashall, C, Chambers, K C, Denneau, L, Flewelling, H A, Heinze, A, Holoien, T W-S, Huber, M E, Kochanek, C S, Mazzali, P A, Prieto, J L, Rest, A, Shappee, B J, Stalder, B, Stanek, K Z, Stritzinger, M D, Thompson, T A & Tonry, J L 2018, ' The Cow: Discovery of a Luminous, Hot, and Rapidly Evolving Transient ', The Astrophysical Journal Letters, vol. 865, no. L3, pp. 1-8 . https://doi.org/10.3847/2041-8213/aadd90, Astrophys.J., Astrophys.J., 2018, 865 (1), pp.L3. ⟨10.3847/2041-8213/aadd90⟩, The Astrophysical Journal, Astrophys.J.Lett., Astrophys.J.Lett., 2018, 865 (1), pp.L3. ⟨10.3847/2041-8213/aadd90⟩
Accession number :
edsair.doi.dedup.....bdd5ff8cef99840460756a13ae177376