A study of the Type II-P supernova 2003gd in M74 |
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| Authors: | M A Hendry S J Smartt J R Maund A Pastorello L Zampieri S Benetti M Turatto E Cappellaro W P S Meikle R Kotak M J Irwin P G Jonker L Vermaas R F Peletier H van Woerden K M Exter D L Pollacco S Leon S Verley C R Benn G Pignata |
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| Institution: | Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA;Department of Physics and Astronomy, Queen's University Belfast, Belfast BT7 1NN;INAF –Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy;INAF –Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova, Italy;INAF –Osservatorio Astronomico di Capodimonte, Via Moiariello 16, I-80131 Napoli, Italy;Astrophysics Group, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ;Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA;Kapteyn Instituut, Postbus 800, 9700 AV Groningen, the Netherlands;Instituto de Astrofísica de Canarias, C/Vía Láctea s/n, E38200 La Laguna (Tenerife), Spain;School of Pure and Applied Physics, Queen's University Belfast, Belfast BT7 9NN;Instituto de Astrofísica de Andalucía (CSIC), Apartado 3004, 18080 Granada, Spain;Isaac Newton Group, Apartado 321, E38700 Santa Cruz de La Palma, Spain;European Southern Observatory (ESO), Karl-Schwarzschild-Str. 2, D-85748 Garching bei München, Germany |
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| Abstract: | We present photometric and spectroscopic data of the Type II-P supernova (SN II-P) 2003gd, which was discovered in M74 close to the end of its plateau phase. SN 2003gd is the first Type II supernova (SN) to have a directly confirmed red supergiant (RSG) progenitor. We compare SN 2003gd to SN 1999em, a similar SN II-P, and estimate an explosion date of 2003 March 18. We determine a reddening towards the SN of E ( B ? V ) = 0.14 ± 0.06 , using three different methods. We also calculate three new distances to M74 of 9.6 ± 2.8, 7.7 ± 1.7 and 9.6 ± 2.2 Mpc . The former was estimated using the standard candle method (SCM), for Type II supernovae (SNe II), and the latter two using the brightest supergiants method (BSM). When combined with existing kinematic and BSM distance estimates, we derive a mean value of 9.3 ± 1.8 Mpc . SN 2003gd was found to have a lower tail luminosity compared with other normal Type II-P supernovae (SNe II-P) bringing into question the nature of this SN. We present a discussion concluding that this is a normal SN II-P, which is consistent with the observed progenitor mass of 8+4?2 M⊙ . |
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| Keywords: | stars: evolution supernovae: general supernovae: individual: SN 2003gd galaxies: distances and redshifts galaxies: individual: M74 |
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