[vsnet-chat 978] Re: Host galaxy of SN1998cl

[Yamaoka Hitoshi <yamaoka@rc.kyushu-u.ac.jp>]

Dear all,

Dr. Kato has kindly provided the chart and the information of the host
galaxy of SN 1998cl.  I would like to give some additional notes. 

>Host galaxy of SN1998cl

The very host galaxy (Markarian 261 = A1329+75A = PGC 47417 = CGCG
353-17) shows a bit irregular shape, whose center is R.A. =
13h30m00s.42, Decl. = +75o34'08".9 (2000.0) derived from DSS1 image. 
If the position of SN 1998cl reported on IAUC 6934 (R.A. =
13h29m59s.8, Decl. = +75o34'09".0 was enough accurate and not derived
from the position of the host galaxy, the offset would be estimated as
2" west and 0" south from the core (on IAUC, it was reported as 5"
west and 1" north). 

> 132959.9 +753333 (2000.0) CfA_13290+7550 v=9290km/s Bmag=15.3
> 133000.4 +753355 (2000.0) RC3_A1329+75A PGC47417
> 133000.5 +753357 (2000.0) A1329+75A

These three seems to point this host. 

In the neighbourhood of the host galaxy, there are at least 2 galaxies
which seem to make a group with Markarian 261.  The next brightest one
is Markarian 262 = A1329+75B = PGC 47454, which seems to be a
nearly-edge-on spiral. The angular distance between Markarian 261 and
262 is about 66", which is correspond to 50kpc at the distance of
150Mpc (H_0 is assumed to be 60 km/s/Mpc and v_r = 9000 km/s for
Markarian 261/262).  

> 133017.6 +753333 (2000.0) CfA_1329+7549B v=8991km/s Bmag=16.0
> 133018.7 +753357 (2000.0) A1329+75B
> 133019.0 +753358 (2000.0) RC3_A1329+75B PGC47454

These three are pointing to Markarian 262.

> 133004.6 +753406 (2000.0) IRAS13291+7549 0.250L 0.250L 0.961 1.852 -1%
> 133004.6 +753406 (2000.0) SSC13291+7549 0.250L 0.250L 0.961 1.852
> 133006.9 +753350 (2000.0) FSC13292+7549 0.093 0.081 0.985 1.923

These three seem to point the pair of Markarian 261/262.

> 133005.9 +753459 (2000.0) RC3_A1329+75C PGC47431

This is another faint galaxy. NED position of this galaxy is about 30"
north than accurate position. RC3 position (above) is good. This
galaxy can be a colliding pair or triplet.  About 1'30" north and 30"
west of this galaxy (A1329+75C), there exist another colliding galaxy.

At Markarian 261 distance, typical SNe Ia will glow at about 17 mag at
its maximum.  

Markarian 261 (the host of SN 1998cl) seems to have a blobby nature.
The photometric observer should be careful in identifying the SN.  A
dim knot (>18 mag) are there at about 10"W,10"S from the center. But
it is uncertain whether it is real or not, because I can scan only
DSS1 image.  A foreground star are there at about 25"W,20"N.  

Markarian 262 has also a confusing foreground star at 7"W,10"S from
its center. 

Sincerely Yours,
Hitoshi Yamaoka, Kyushu Univ., Japan
yamaoka@rc.kyushu-u.ac.jp

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