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Alert Notice 495: Bright Type-Ia Supernova PSN J09554214+6940260 and Observing Campaign

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January 22, 2014

Event: Supernova in M82 (Ursa Major) = PSN J09554214+6940260

Discovery by: Stephen J. Fossey (University College London Observatory)

Discovery magnitude
: 11.7 V

Discovery date: 2014 January 21.81 UT

Coordinates: R.A. = 09 55 42.15, Decl.= +69 40 25.8 (2000.0)
PSN J09554214+6940260 is offset 54" west, 21" south from the nucleus of M82

Spectra: PSN J09554214+6940260 is a reddened young Type-Ia supernova discovered before maximum, according to a report by Y. Cao (Caltech), M. M. Kasliwal (Carnegie/Princeton), A. McKay (UT Austin), and A. Bradley (APO) on behalf of the intermediate Palomar Transient Factory Collaboration of spectra obtained on 2014 Jan. 22.305 UT using the Dual Imaging Spectrograph on the ARC 3.5m telescope (ATel #5786, http://www.astronomerstelegram.org/?read=5786). They also report the best superfit match is SN2002bo at -14d, and that the supernova has a red continuum and deep Na D absorption.

Observing Campaign: Both visual and CCD observations are encouraged. Please use the available sequence from VSP. CCD observers are encouraged to perform filtered photometry, and if possible to transform their observations to the standard photometric system of their filters.

In addition to photometric follow-up of this supernova by our visual and instrumental observers, rapid V-band time-series has been requested by Dr. Bradley Schaefer (Louisiana State University) for an exploratory search for possible flares or other short-term photometric variations during the outburst. Dr. Schaefer writes:

"Fast variability is *not* expected from supernovae (because the shell is too large to change fast), but then no one has ever looked. Similarly, no one [expected] fast variations from novae during their optically-thick shell phase, but the first time anyone looked, for U Sco in 2010, the nova was seen to have many hour-long flares, with these still being completely unexplained.

"The M82 SN is bright and well-placed in the sky, so AAVSO people can get fast time series with good photometric accuracy and long time coverage. Importantly, many observers are needed, because any flare (or dip) will have to have independent confirmation. And this means that many observers are needed so that we can always get overlapping time series....

"Keep on the supernova all night for as long as you can. Long time series improves your chances of catching a perhaps-infrequent flare/dip, improves the baseline for detecting flare/dips, and makes for more observers catching a flare/dip as independent confirmation."

Dr. Schaefer requests observations with S/N of 100 or better (errors of 0.01 magnitude or less), made with a V filter. Observers are encouraged to follow this object for as much of the night as possible and for as long as possible during the outburst. Please use comparison stars provided via AAVSO charts.

Observations reported to the AAVSO (see Note a)
:
2014 Jan. 03.77-03.81 UT, <19.6 unfiltered (D. Denisenko, V. Lipunov, and E. Gorbovskoy, MASTER-Kislovodsk triplet exposures, combined limiting mag);
13.56-13.59, <18.5 unfiltered (Denisenko, Lipunov, and Gorbovskoy, MASTER-Amur triplet exposures, combined limiting mag);
13.591, <17.0 unfiltered (K. Itagaki, Yamagata, Japan (0.50-m f/6.8 refl.+CCD);
14.559, <17.0 unfiltered (Itagaki);
15.571, 14.4 unfiltered (Itagaki);
16.641, 13.9 unfiltered (Itagaki);
17.612, 13.3 unfiltered (Itagaki);
19.618, 12.2 unfiltered (Itagaki);
20.620, 11.9 unfiltered (Itagaki);
22.1504 UT, 12.96 B (S. Kiyota, Kamagaya, Japan, confirmation image, remotely using 0.43m Astrograph+FLI FLI-PL6303E CCD camera (T21, iTelescope.NET, Mayhill, NM);
22.1504, 11.68 V (Kiyota, confirmation image);
22.1504, 11.04 Rc (Kiyota, confirmation image);
22.1504, 10.63 Ic (Kiyota, confirmation image);
22.3, 11.3 unfiltered (E. Guido, N. Howes, and M. Nicolini, confirmation image, remotely using 0.50-m f/6.8 astrograph+CCD+f/4.5 focal reducer from MPC Code H06 (iTelescope, New Mexico);
22.33515, 10.925 R +/-0.041 (WXR, R. Wahlstrom, Alingsas, Sweden);
22.33404, 12.992 B +/-0.032 (Wahlstrom);
22.33278, 11.687 V +/-0.037 (Wahlstrom);
22.3955, 12.91 B (L. Elenin, Lyubertsy, Russia, and I. Molotov, Moscow, Russia, confirmation image, remotely using 0.4-m f/3 telescope+CCD at ISON-NM Observatory, Mayhill, NM);
22.4061, 11.31 R (Elenin and Molotov, confirmation image);
22.4066, 11.33 I (Elenin and Molotov, confirmation image);
22.4101, 11.72 V (Elenin and Molotov, confirmation image);
22.42167, 10.862 R +/-0.002 (WTHB, T. Wikander, Borlange, Sweden);
22.42025, 11.633 V +/-0.003 (Wikander);
22.41844, 12.925 B +/-0.01 (Wikander);
22.43508, 12.9 B (T. Yusa, Osaki, Japan, remotely using 0.43-m f/6.8 astrograph+CCD+f/4.5 reducer, iTelescopeNET Mayhill, NM);
22.43508, 11.3 V (Yusa);
22.43508, 10.9 R (Yusa);
22.43508, 10.3 Ic (Yusa);
22.466, 11.56 CV +/-0.35 (J. Brimacombe, Cairns, Australia);
22.490, 11.4 unfiltered (T. Noguchi, Chiba-ken, Japan, 0.23-m f/6.3 Schmidt-Cassegrain+CCD);
22.727 11.2 CR (G. Masi, F. Nocentini, and P. Schmeer, remotely using the 17"-f/6.8 robotic unit part of the Virtual Telescope Project facility in Ceccano, Italy);   

Charts: Charts for PSN J09554214+6940260 may be created using the AAVSO/vspVariable Star Plotter (VSP) at http://www.aavso.org/vsp.

Submit observations: Please submit observations to the AAVSO International Database using the name PSN J09554214+6940260.

Notes:
a. Initially reported on IAU Transient Object Confirmation Page (TOCP) webpage (http://www.cbat.eps.harvard.edu/unconf/tocp.html). Except for the spectroscopy reported in ATel #5786 or for observations reported to the AAVSO by T. Wikander and R. Wahlstrom or information sent to the AAVSO online forum (http://www.aavso.org/forum), all information in this Alert Notice is from the CBAT TOCP.

b. The supernova was designated PSN J09554214+6940260 when it was posted on the CBAT TOCP webpage.
 
c. Confirmed by
- Seiichiro Kiyota (Kamagaya, Japan) on 2014 January 22.1504 UT (observations above) using TYC 4383-2050-1 as a comparison.  
- Ernesto Guido, Nick Howes & Martino Nicolini on Jan 22.3690 UT (observations above) using UCAC-3 catalogue reference stars).
- V. Lipunov et al. on behalf of the MASTER team on Jan. 22.399 UT using MASTER-Amur robotic telescope (presence confirmed but mag too bright).
- L. Elenin (Lyubertsy, Russia) and I. Molotov (Moscow, Russia) on Jan. 22.3955 UT (observations above) using UCAC-4 reference stars.

d. Elenin and Molotov report nothing is visible at this position on the archive POSS and POSSII images.

e. C. Yao et al. note (ATel #5786, http://www.astronomerstelegram.org/?read=5786) that the supernova is visible in Palomar 48-inch images taken 2014 Jan 21.158 but is too saturated to measure a magnitude. Prior to Jan 13, iPTF upper limits are <20.4 R.

f. A press release from the University College London regarding Fossett's observations and including the discovery image is available at http://www.ucl.ac.uk/maps-faculty/maps-news-publication/maps1405.

g. PSN J09554214+6940260 images:
- D. Denisenko, V. Lipunov and E. Gorbovskoy (stacked MASTER images of Jan. 03 and Jan. 13) at http://master.sai.msu.ru/static/OT/M82-2014Jan03-13-MASTER.jpg.
- S. Kiyota (Jan 22.1504, 11.68V, confirmation image), at http://meineko.sakura.ne.jp/ccd/PSN_J09554214+6940260.jpg.
- E. Guido, N. Howes, and M. Nicolini (Jan 22.3, 11.0 R, confirmation image), at http://bit.ly/1aIuXPr.
- Guido et al. (Jan 22.3, comparison between image and POSS2/UKSTU plate (R filter,1998) at http://bit.ly/KDLScg.
- V. Lipunov et al. on behalf of the MASTER team (Jan 22.399, 9.7 (too bright, calibrated vs 0.2B + 0.8R) at http://master.sai.msu.ru/static/M82_SN.png.
- L. Elenin and Molotov (Jan. 22.4101, 11.72V) at http://spaceobs.org/images/TOCP/PSNJ09554214+6940260-20140122.png.
- K. Itagaki prediscovery images (observations above) at http://www.k-itagaki.jp/psn-m82.jpg.
- T. Yusa (Jan. 22.43508, 11.3 V) at http://space.geocities.jp/yusastar77/supernova/PSNinM82_140122.htm.
- J. Brimacombe (Jan. 22.466, 11.56 CV) at http://www.flickr.com/photos/43846774@N02/12086849523/.
- T. Noguchi (Jan. 22.490, 11.4 V) at http://park8.wakwak.com/~ngc/images/PSNinM82.jpg.

h. Position end figures
- Guido et al. (Jan. 22.3, 2014) 42.17s, 25.9"
- L. Elenin (Lyubertsy, Russia) and I. Molotov (Moscow, Russia) 42.15s, 25.8"
- T. Yusa (Jan. 22.43508) 42.14s, 25.7"
- J. Brimacombe (Jan. 22.466) 42.13s, 26.0"
- T. Noguchi (Jan. 22.490) 42.18s, 25.8"
- Masi et al. (Jan. 22.727) 42.14s, 25.9"

Congratulations to Stephen Fossey on his discovery!

This AAVSO Alert Notice was prepared by Elizabeth O. Waagen and Dr. Matthew Templeton.

Spanish version

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