[IAUC] CBET 4184: 20151117 : SUPERNOVA 2015ak IN ESO 108-21 = PSN J22151967-6532534

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                                                  Electronic Telegram No. 4184
Central Bureau for Astronomical Telegrams
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SUPERNOVA 2015ak IN ESO 108-21 = PSN J22151967-6532534
     Peter Marples, Loganholme, Queensland, Australia, reports the discovery
of an apparent supernova (mag 16.0) on an unfiltered image (limiting red mag
17.5) taken on Aug. 18.54 UT with a 30-cm Meade LX200ACF f/7 reflector; the
new object is located at R.A. = 22h15m19s.67, Decl. = -65d32'53".4 (equinox
2000.0), which is 18" east and 6" north of the center of ESO 108-21.  Nothing
is visible at this position on Digitized Sky Survey red and infrared images
(limiting red mag 19).  The variable was designated PSN J22151967-6532534
when it was posted at the Central Bureau's TOCP webpage and is here
designated SN 2015ak based on the spectroscopic confirmation reported below.
Additional CCD magnitudes for 2015ak:  Aug. 2.57, [17.5 (Marples); 10.435,
18.7 (S. Parker, Canterbury, New Zealand; limiting mag 19; pre-discovery
image); 18.55, 16.0 (G. Bock, Runaway Bay, Gold Coast, Qld., Australia);
19.729, 17.0 (J. Brimacombe, Cairns, Australia; position end figures 19s.52,
53".6; image posted at https://www.flickr.com/photos/43846774@N02/20732971441/).

     G. Hosseinzadeh, I. Arcavi, S. Valenti, C. McCully, and D. A. Howell, Las
Cumbres Observatory Global Telescope Network and University of California,
Santa Barbara, report that a spectrogram of PSN J22151967-6532534 = SN 2015ak,
obtained on Aug. 19.4 UT with the FLOYDS robotic spectrograph (range 320-1000
nm, resolution 2 nm) mounted on the 2-m "Faulkes Telescope South" at Siding
Spring Observatory, Australia, shows it to be a type-Ia supernova.  Using
SNID (Blondin and Tonry 2007, Ap.J. 666, 1024), they find a good fit to the
normal type-Ia supernova 1999ee at nine days before maximum light at the
redshift of the proposed host galaxy (z = 0.010; Ramella et al. 1996, A.Ap.
312, 745; via NED).


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                         (C) Copyright 2015 CBAT
2015 November 17                 (CBET 4184)              Daniel W. E. Green