In questa pagina vengono riportate tutte le notizie documentate sulla Supernova 2000C dal 12 gennaio 2000, giorno della sua scoperta.
Documento 1. 12 gennaio: immagine originale della scoperta
Documento 2. 13 gennaio: messaggio inviato a Mirko Villi per segnalare la scoperta della presunta Supernova
Documento 3. 13 gennaio: prima risposta dall'ISN Alert di David Bishop
Interesting. This object appears to be at
almost the same position as
1998Y (which was 7" east and 6" north of NGC 2415)
References:
http://www.ggw.org/asras/snimages/sn1998.html#1998Y
http://astron.berkeley.edu/~bait/1998/sn98y.html
(image rotated)
I checked several images of this galaxy from:
http://www.ggw.org/asras/snimages/snlinks.html#References
and, though most of them are washed out, I see no stars at this position
--
David W. Bishop
Documento 4. 13 gennaio: seconda risposta dall'ISN Alert
Best of luck -
Mike
Documento 5. 13 gennaio: terza risposta e conferma dal LOSS
Documento 6. 14 gennaio: composto messaggio ufficiale di conferma di Alessandro Dimai
Caro Marco,
Documento 7. 14 gennaio: altro messaggio dall'ISN Alert in cui si caldeggia una spettroscopia a brevissimo tempo
Dear SN watchers,
I think that the information like this (confirmed by several
observers) should be widely distributed even before the announcement
of IAU Circular, but because the original discovery information was
posted to isn_alert which is closed ML, I limit this only to isn_alert
now.
An Italian astronomer M. Migliardi has discovered an apparent
supernova (15.5-16.0 mag) in NGC 2415 on Jan. 12.95 UT, and confirmed
by the discoverer and W.D. Li at the LOSS KAIT. The position derived
from the discovery image is: R.A. = 7h36m57s.09, Decl. = +35o14'38".8
(2000.0), which is 8".3 east and 7".4 north of the nucleus of NGC
2415. The position of nucleus was measured on the same image, which
has position end figures 56s.41, 31".4 (the uncertainty would be
larger than 1" order; see below).
The host galaxy is somewhat irregular one, having bright barred
nucleus (east to west) and surrounding disk. The possible SN is
superposed on the northeastern part of the disk. The eastern end of
the barred nucleus is possibly a foreground star, but the nature of it
is uncertain.
As D. Bishop has pointed out, SN 1998Y was observed on the very near
position of the current one. The position of SN 1998Y was reported as
R.A. = 7h36m56s.93, Decl. = +35o14'36".0 (2000.0) on IAUC 6850. The
current one is slightly north than SN 1998Y.
The recession velocity of the host galaxy is about 3800 km/s, from
which the expected maximum of SNeIa on this galaxy is about 15.0 mag.
SN II 1998Y was observed as 18.3 mag. The current SN seems a bright
SN like as SN Ia. The followup spectroscopy and magnitude estimates
are urged.
Sincerely Yours,
Hitoshi Yamaoka, Kyushu Univ., Japan
Documento 10. 17 gennaio: messaggio di Dan Green dove compare per la prima volta il nome del co-scopritore, S.Foulkes
On March 26, 1998, we announced SN 1998Y in NGC 2415,
discovered by LOSS -- typed as a type-II supernova.
Now we have reports from Marco Migliardi in Italy and
from Steven Foulkes in England (via Mirko Villi and
Guy Hurst, respectively) of an apparent "new" supernova
located at almost precisely the same position as
SN 1998Y. Can you check to see if this could be
a secondary outburst of SN 1998Y (in which case it'd
be quite interesting) or possible a new supernova located
at almost the same location as SN 1998Y (something I'd
think to be less likely).
Position from Weidong Li is
R.A. = 7h36m56s.99, Decl. = +35 14' 37".2 (2000.0),
7".7 east and 7".2 north of the galaxy's nucleus.
Documento 11. 18 gennaio: messaggio di Yamaoka sul ritardo nell'ufficializzazione
Dear Drs. Dimai and Migliardi,
I wish to congratulate your discovery of the probable SN in NGC
2415! There are many confirmation of the existence, so I believe it
is at least a new object outside of our solar system.
As you know, I have posted an information about this object in order
to make further attention to the follow-up observations. But the
posting was restricted to isn_alert, which is not so widely
distributed. Can I send the information to other (more public) MLs or
by other method? Also as you know, the D. Bishop's fine page
(http://www.ggw.org/asras/snimages)
has mention the possible SNe, now
including yours. He had been waiting the report on IAUC, but it seems
to delay for recent cases.
I think that the most important thing to make the discovery fruitful
is the rapid circulation of the informations. If you agree this,
please reply me as soon as possible.
Sincerely Yours,
Hitoshi Yamaoka, Kyushu Univ., Japan
Documento 12. 18 gennaio: anche Cesare Barbieri cerca di sollecitare uno "spettro" della SN
Documento 13. 18 gennaio: scambio epistolare fra noi e Yamaoka sempre in merito ai ritardi nell'ufficializzazione
>Please, do you have some news of our supernova in NGC 2415?
>Why Mr. Green don't announced this discovery?
I guess that CBAT (Drs. Marsden, Green, ...) is waiting the
spectroscopy. They probably want to notice it after it will be clear
that it is really SN. My opinion is, of course, differ from them.
This object doubtlessly exist, and it is clear to be wildly-variable
star lying outside the solar system. The explosive event, like as
supernovae, will changes their feature with time, and the earlier
feature will never be reproduced by the later observations. The
earlier feature reveals the outer region of the expanding object,
which will become transparent (cannot be observed) some time after. I
wish to apologize that the SN community cannot make the wider research
after your valuable discovery till now.
>It's possible for you or your friends to take a spectrum of this
>object and confirm it?
Actually, the Japanese coleague has tried to get the spectrum on
Jan. 14 UT. I have saw that, but because of the low altitude and the
dim nature (mag 16 is near to the limit of 1-m class telescope for the
spectroscopy), I could not define whether it is really SN or not.
We decided not to report it because of the low quality, so please keep
only for you about this information. In successive days, we cannot
observe it because of the unsteadiness of the weather.
>Please send the information to other observatories for a
>spectroscopic confirmation of our SN in ngc2415.
Thank you very much. However, I have received the objection to do
it from the other subscribers of isn_alert (I have posted the request
for consent also to it). Now, I have to wait some to distribute the
information widely....
Sincerely Yours,
Hitoshi Yamaoka, Kyushu Univ., Japan
Documento 14. 19 gennaio: finalmente l'ufficializzazione con
la circolare IAU n°7348
SUPERNOVA 2000C IN NGC 2415 Independent
discoveries of a new apparent supernova in NGC 2415 have been made by Steven
Foulkes, Ashperton Village, England, on Jan. 8.789 UT (communicated via G.
Hurst) and by Marco Migliardi, Cortina, Italy, on Jan. 12.95 (via M. Villi).
Foulkes' discovery was made on an unfiltered CCD image taken with a 0.26-m
reflector in the course of the U.K. Nova/Supernova Patrol. Migliardi obtained
the following position for SN 2000C from his discovery image: R.A. =
7h36m57s.09, Decl. = +35o14'38".8 (equinox 2000.0), which is 8".3 east
and 7".4 north of the nucleus of NGC 2415. W. Li, University of California
at Berkeley, reports that a prediscovery image (limiting mag 19.5-20.0) of SN
2000C appears on a CCD frame taken on Jan. 8.3 with the Katzman Automatic
Imaging Telescope (KAIT) at Lick Observatory, from whence he provides the
following position end figures: 56s.99, 37".2. Li adds that although SN
2000C is very close to the location of SN 1998Y (cf. IAUC
6850), comparison with KAIT images of SN 1998Y shows that the new object is
slightly north and east of SN 1998Y (see http://astron.berkeley.edu/~bait/2000/ngc2415.html);
he also notes that SN 1998Y faded from view on KAIT images in Oct. 1998.
Estimated magnitudes for SN 2000C: 1999 Dec. 15.995, [17: (Foulkes); 26, [19.0
(Li); 30, [18.5 (Li); 2000 Jan. 4, 19.5-20.0 (Li; only hint of new object); 8.3,
18.0: (Li); 8.789, 15.6: (Foulkes); 12.95, 15.5 (Migliardi).
Documento 15. 20 gennaio: altre notizie sulla galassia ospite
Dear SN watchers, As IAUC 7348 informed, SN 2000C has been discovered on Jan. 8.789 UT by an English astronomer S. Foulkes, and on Jan 12.95 UT by an Italian astronomer M. Migliardi. The report has been delayed about 10 days (!) after its discovery. The position derived from the discovery image is: R.A. = 7h36m57s.09, Decl. = +35o14'38".8 (2000.0), which is 8".3 east and 7".4 north of the nucleus of NGC 2415. The position of nucleus was measured on the same image, which has position end figures 56s.41, 31".4 (the uncertainty would be larger than 1" order; see below). Also W.D. Li, the LOSS KAIT term, provided the position of SN 2000C end figures as 56s.99, 37".2, which agrees well with above. The host galaxy is somewhat irregular one, having bright barred nucleus (east to west) and surrounding disk. The possible SN is superposed on the northeastern part of the disk. The eastern end of the barred nucleus is possibly a foreground star, but the nature of it is uncertain. As D. Bishop, ISN, has pointed out, SN 1998Y was observed on the very near position of the current one. The position of SN 1998Y was reported as R.A. = 7h36m56s.93, Decl. = +35o14'36".0 (2000.0) on IAUC 6850. The current one is slightly north and east of SN 1998Y, which is shown on http://astron.berkeley.edu/~bait/2000/ngc2415.html . The recession velocity of the host galaxy is about 3800 km/s, from which the expected maximum of SNeIa on this galaxy is about 15.0 mag. SN II 1998Y was observed as 18.3 mag. The current SN seems a bright SN like as SN Ia. The followup spectroscopy and magnitude estimates are urged. Sincerely Yours, Hitoshi Yamaoka, Kyushu Univ., Japan yamaoka@rc.kyushu-u.ac.jp
Documento 16. 23 gennaio: avanza la possibilità che si tratti di una hypernova
Dear SN watchers, Yasuo Sano has reported the bright magnitude (144C or 147C: depending on the reference stars) for SN 2000C at Jan.18.5 UT It is quite brighter than typical SNeIa or SN 1998bw hyprenova model. The followup observations and spectroscopical type determination (or whether it is SN or not) are surely important for this object regretably left without published about its discovery. Sincerely Yours, Hitoshi Yamaoka, Kyushu Univ., Japan yamaoka@rc.kyushu-u.ac.jp
Documento 17. 24 gennaio: stime di magnitudine
SN2000C bright! As suggested by Yamaoka and Sano, SN2000C is observed very bright! YYYYMMDD(UT) mag observer 19991215.994 <170C (S. Foulkes (from IAUC)) 20000108.300 180C (KAIT (from IAUC)) 20000108.789 156C (S. Foulkes (from IAUC)) 20000112.949 155C (M. Migliardi (from IAUC)) 20000120.104 144V (L. Robinson) 20000120.107 142V (L. Robinson) 20000120.108 145V (L. Robinson) 20000120.110 142V (L. Robinson) 20000123.267 145V (L. Robinson) 20000123.285 147V (L. Robinson)
Documento 18. 28 gennaio: risultati della spettrografia. Tipo Ic
E. Cappellaro and M. Turatto, Osservatorio Astronomico di Padova, report
that spectra of SN~2000C (cf. IAU 7348) have been obtained by A.
Pizzella, E.M. Corsini, and D. Moro with the Asiago 122cm telescope +
B&C spectrograph on Jan 25.9 UT and by G. Galletta with the 1.8m
telescope + AFOSC on Jan 27.9 UT
(range 350-750 nm, resolution 2nm).
The calibrated spectra are very similar to that of the type Ic SNe
SN1987M and 1990aa 1-2 weeks after maximum (cf. Filippenko et al. 1992,
ApJ 384, L37)
with prominent CaII and FeII features. Also visible is an absorption at
625 nm which, if attributed to SiII6355 as in the case of SN1987M,
indicates an expansion velocity of about 9000 km/s.
Therefore, despite the apparent coincident location, SN 2000C is a
distinct object from SN 1998Y.
Documento 19. 30 gennaio: richiesta di nuove ricerche
Dear SN watchers, According to IAUC 7352, the Asiago group and the CfA group has determined as type Ic supernovae around maximum. Both says that it resembles to that of typical SN Ic 1987M. The brightness of SN 2000C is, however, very brighter than typical SNeIc, if the reported magnitude estimates are accurate. It is quite varuable to get a light curve for this bright SN Ic for exploring the nature of it. Sincerely Yours, Hitoshi Yamaoka, Kyushu Univ., Japan yamaoka@rc.kyushu-u.ac.jp
Documento 20. 2 febbraio: nuova circolare IAUC 7356
SUPERNOVA 2000C IN NGC 2415 Unfiltered CCD magnitudes: Jan. 21.198 UT, 15.00 (M. Suarez, Las Palmas, Canary Islands); 25.697, 14.8 (S. Yoshida and K. Kadota, Ageo, Saitama, Japan).