PSN J09554214+6940260 in M82 - mag V 11.7

[Paolo Berardi]

Discovery: Stephen J. Fossey
First follow-up by Seiichiro Kiyota.

Nicely placed in the sky!

http://www.cbat.eps.harvard.edu/unconf/ ... 40260.html

Image:
http://meineko.sakura.ne.jp/ccd/PSN_J09 ... 940260.jpg

Paolo

EDIT: discovery name corrected

[Paolo Berardi]

Hi all, we were able to observe the SN this night in a small window between clouds. We used Lhires III spectrograph with 150 l/mm grating, only 20 minutes total exposure.



The spectrum confirms a reddened continuum and the strong sodium (D1D2) narrow absorption suggests an interstellar origin of these effects.

First two results from Gelato automatic comparison:





Ciao
Paolo and Giuseppe

[David Boyd]

PSN J09554214+6940260_20140122_960_D.Boyd.png (9.11 KiB) Viewed 21936 times

Spectrum on the supernova in M82 taken tonight with C11 + LISA, 30x3min. Clear but very damp conditions.

Photometry at the same time gave
B = 12.78
V = 11.49
R = 10.72
I = 10.31

David

[Robin Leadbeater]

A spectrum from tonight using a prototype high dispersion Star Analyser mounted in a filter wheel just 26mm from the camera sensor giving R~120 at 6000A. It confirms a reddened type 1a supernova.
I have overlaid Paolo's spectrum from last night for comparison

Cheers
Robin

[Paolo Berardi]

Hi all, a new observation of 25 jan with Lhires III 150 and about two hours integration,



SN should be around mag V 11. During exposures we had several cloud passages and turbulence was very strong. We estimate an FWHM of about 6 arcsec, with star images much more wider than the slit aperture (30 micron). I think there was a huge efficiency loss. This is a guide camera frame, note the star size compared to slit aperture:



Fortunately that is not a normal situation from my observing site!

Follows a comparison that shows spectrum evolution from 22 to 25 jan. Envelope expansion velocity derived from Si II minimum has decreased from about 14400 to 12800 Km/s. A similar trend (decreasing) seems to be shown by other absorption lines.



The slit also captured H-alpha + NII emissions of a nearby region (Lhires III slit view and spectrum):



Considering scale and angle, emission should be related to highlighted area in this wonderful M82 image by HST (original at http://en.wikipedia.org/wiki/File:M82_H ... ge_web.jpg):



Sorry for a such long post... I'm sending fit to François.

Ciao
Paolo

[Francois Teyssier]

Thank you for this acurate description Paolo

According to ATel 5818, the interstellar extinction is E(B-V) = 1.2
which confirms your continuum and the strong Na I D interstellar line

François


ATEL #5818 ATEL #5818

Title: SN2014J spectroscopic and photometric data
Author: INAF-Astronomical Observatory of Bologna
Queries: giuseppe.altavilla@oabo.inaf.it
Posted: 27 Jan 2014; 10:44 UT
Subjects:Optical, Star, Supernovae

Spectra and BVR images of the supernova SN 2014J in the nearby galaxy M82
were obtained on
Jan. 23.05 2014 (UT) a the 1.5m G.D. Cassini Telescope (Loiano) with BFOSC
by G. Altavilla, R. Gualandi and I. Bruni. The spectra, obtained with gr4,
gr7 and gr8 and a 2" slit, cover the ~3500-8000 A range with a resolution
of ~12, ~6 and ~6 A respectively. The expansion velocity measured from
the SiII line (6355A) is ~13900km/s while SII (5640)A gives ~12000 km/s.

The best matches obtained with the GEneric cLAssification TOol (GELATO,
Harutyunyan et al. 2008, A.Ap. 488, 383; available at URL https://gelato.tng.iac.es/login.cgi)
are with SN2000fa (Ia at 12 days before maximum) and SN1997do (Ia at 8
days before maximum).
Magnitude estimates for the same night (JD 2456680.55208) are the following:
B=12.72+-0.14, V=11.52+-0.23, R 11.05 +-0.05. To be noted the corresponding
colour: B-V=1.2 (instead of B-V~0 for a normal type Ia at the same epoch),
supported by the strong NaD features visible in the spectra.

[Paolo Berardi]

Very interesting Francois. I also got a good fit with SN 1997do if I simulate a de-redden from E(B-V)=1 (spectrum of 22 jan).

http://quasar.teoth.it/forums/download/ ... &mode=view

Do ATel mention B-V, not IS reddening? The problem seems that there is an upper limit because the SN is already too bright, considering the distance, for an E(B-V) high value.

Now the SN has reach about mag V 10.7. We hope continue to grow!

See you soon!
Paolo

[Francois Teyssier]

Excellent ! Paolo
That matches very well

Yes, ATel gives B-V and compares the value to expected B0-V0= 0 value (without reddening)
*B-V=1.2 (instead of B-V~0 for a normal type Ia at the same epoch)"
So you get E(B-V) = (B-V) - (B0-V0) = 1.2

Ciao,

François

[Tony Heidemann]

Hello,

here is my first spectrum of SN2014J.
Date: 24/01/2014
Observatory: SMU Castor
Instrument: CN212/3.9 Alpy 600 ST7
Autoguider lodestar.
Exp time 22*300s.

http://astrosurf.com/heidemann/sn2014j.png

clear skies

Tony Heidemann

St. Martin d'Uriage ( France)

[Francois Teyssier]

Le spectre de Tony Heidemann