[vsnet-alert 8637] (fwd) New var near M27 (Renz)

Wed Aug 24 08:43:55 JST 2005

   Message from Wolfgang Renz:

From: "Wolfgang Renz" <w_renz at onlinehome.de>
Subject: Re: Fw: New object near M27
Date: Tue, 23 Aug 2005 17:01:32 +0200

Hello Robert, Hello Phil

That are the two faintest stars with with Henden photometry near the
new object:
# Name RA(J2000) raerr DEC(J2000) decerr nobs V B-V U-B V-R R-I Errors
M27 299.962649 0.104 22.709794 0.065 9 18.745 1.329 99.999 0.356 0.779 =
0.103 0.063 9.999 0.072 0.102
M27 299.963127 0.429 22.708488 0.241 9 19.378 1.246 99.999 0.181 0.962 =
0.170 0.147 9.999 0.125 -9.999

In your image http://www.robertb.darkhorizons.org/m27.htm
you marked the 18.745 magV star with the red cross. The 19.378
magV star is just above the lower streak (this one is scrambled with
a 20.x mag star in your images; maybe also in Arne's photometry).
The new object should be about 1/4th of their distance above the
fainter one.=20
The progenitor might be one of the two fainter stars in Arne's 26
magR image that are not in your image. If it is one of them, then
the outburst amplitude would be less than 10 mag. Thats at the
lower range for a classical nova (8-15 mag) but would be OK for
a recurrent nova (outburst interval: several decades to much more)
or a WZ Sge star (UGSU stars with infrequent bright super out-
bursts and no normal outbursts; like AL Com, EG Cnc, GW Lib
and WZ Sge; outburst interval: more than 1000 days up to a few
decades). There are also some galaxies in that area (the closest
radio galaxy is just 2.5' away), but they should be too faint (=3D too
far away) to produce such a bright SN.

Take a look at the newest 20" RCOS  image of R Jay GaBany
from last night:
http://www.cosmotography.com/images/imp_m27_nova.html
http://www.cosmotography.com/images/imp_m27_postnova.jpg
On this one it looks like its none of the two. This would make it
more probable that is something with a larger outburst amplitude
than a UGSU/WZ star.

No, I'm not the discoverer of the new object !
Joerg Hanisch and Hans-Goeran Lindberg are the discoverers.

Joerg Hanisch consulted two photometrists in the German BAV
directly on Sunday morning. One was away and the other one
adviced him to consult the BAV-Forum email list. So I got to know
of the object on early Sunday evening.
As usually not many people respond to such requests, I made some
basic checks myself (cosmics, reflections, near MP, new SNs, near
galaxies, not bright in DSS 2 infrared & 2MASS J H Ks). All basic
checkes were OK. Then I started to look in the pretty picture email
lists for recent images of M27 and found an image by Dominik Wos
that showed to new object too. While I prepared my first email,
Hans-Goeran Lindberg reported the new object too.

You must remember that the way it went is not the 'usual' one !
Some people are 'keen on' being named as discoverer and some
publishers give hard restrictions for issuing an announcement. So
'usually' new objects are not announced publicly but confidentially
to a very small circle thats able to confirm the discovery and make
photometry and spectra. If the required data for a paper or an IAUC
is collected, they go public. As this process takes some time
(usually 1 to 10 days), very often valuable time is lost on fast
changing object. Every day it takes longer, no data can be
collected by the rest of the world.
As the new object was already announced publicly there was no
need and possibility to keep it secret by me. Actually I wanted to
see what we amateurs can collect on the new object before the
professionals even hear about it.
With the image of R Jay GaBany it should be possible to identify
a possible progenitor in Arne's 26 magR image. Now we are
just a sprectrum away from an IAUC and an AAVSO Alert.

Sorry to hear that nobody is interested in the Siefert-like jet coming
out of NGC 5943 you found. Maybe someone is interested who
reads this email. Or knows someone who might be interested.

Clear skies
  Wolfgang

--=20
Wolfgang Renz, Karlsruhe, Germany
Rz.BAV =3D WRe.vsnet =3D RWG.AAVSO

----- Original Message -----=20
From: Robert Bateman=20
To: Wolfgang Renz=20
Sent: Tuesday, August 23, 2005 4:40 AM
Subject: Re: Fw: New object near M27

Wolfgang:
  I have examined the stack of images I took Aug 2nd (10 x 15 seconds @ =
16" F/4.5) and I see a very faint star at RA 19h 59m 51.126s DEC +22d =
42' 31.45" with a value of 193 with my background at 190.   A nearby =
star at RA 19h 59m 52.098s and DEC +22d 42' 17.01" with a value of 196 =
and a magnitude calculated by AstroArt @ 18.63.  It's safe to say there =
was nothing in the area just 2 weeks ago that was brighter than 19th =
magnitude.  No matter what type of nova it turns out to be, a nova is a =
nova!
   If you are the discoverer, congratulations.  By coincidence, I found =
a Siefert-like jet coming out of NGC 5943 that same night.  Totally =
unknown, but Mr. Skiff maintains that it is perfectly normal and the =
professional astronomers can waste no time looking at it.  I hope they =
get you better treatment than was afforded me.

RobertB
At 06:06 PM 8/22/2005, you wrote:

FYI
=20
The closest star Arne Henden has in his photometry files is:
RAJ2000: 19:59:51.15
DEJ2000: +22:42:30.6
V mag  : 19.378
(B-V)  :  1.246

You can compare it to Arne's 26 magR image (see link below).
=20
Clear skies
  Wolfgang
=20
--=20
Wolfgang Renz, Karlsruhe, Germany
Rz.BAV =3D WRe.vsnet =3D RWG.AAVSO
=20
=20

----- Original Message -----=20
From: "cust25f45" <robertb at com-pair.net>
To: <SBIG at yahoogroups.com>
Sent: Monday, August 22, 2005 5:09 PM
Subject: [SBIG] Re: New object near M27

> Paul, I have an image of M27 taken on August 2nd, and I have=20
> stars down to 19 mag +- .2 .  I see what I think is a very faint star=20
> at the position indicated.  Very hard to tell, though.
> http://www.robertb.darkhorizons.org/m27.htm
> Is there an official confirmation of SN and J2000 coords for this=20
> yet?
>=20
> RobertB

----- Original Message -----=20
From: "phildombrowski" <phil.dombrowski at cox.net>
To: <SBIG at yahoogroups.com>
Sent: Monday, August 22, 2005 5:47 PM
Subject: [SBIG] re: M27 "nova"

> It appears that you may have caught a "dwarf nova" a.k.a. cataclysmic
> variable star, or perhaps some other type of irregular variable.  I am
> surprised that this object has not been seen over the years in that
> M27 is such a popular photographic target.  If it were a nova (in our
> galaxy) it would likely be much brighter.  Assuming there is not a
> background galaxy in that area of M27 one can rule out a supernova.=20
> As a member of the American Asociation of Variable Star Observers
> (AAVSO) I would have received an Alert Notice on a nova-like object.
>=20
> In any case, that is a great find for its own sake.  Not to forget the
> fact that it is an excellent image with a very fine mouse over =
technique.
>=20
> best,
>=20
> Phil Dombrowski

=20
=20
----- Original Message -----=20
From: arne=20
To: Wolfgang Renz=20
Cc: Aaron Price (AAVSO) ; Dan Green (IAU) ; J=F6rg Hanisch ; =
Hans-G=F6ran Lindberg ; R Jay GaBany=20
Sent: Monday, August 22, 2005 5:08 PM
Subject: Re: New object near M27

I've placed on http://www.aavso.org/tmp2/m27r.jpg
a section of a deeper, better seeing image (USNO-FS 1.55m
telescope, wide R-band, composite over several years in the
mid-990's) than GaBany's nice color image of approximately
the same field.  I do not see any faint galaxy, and the resolution
of the discovery image is not sufficient to immediately identify
the progenitor, though it looks like it is likely one of the faint
objects on this image.  Since the limiting magnitude of my
image is about R=3D26, this makes the total amplitude at least
10 magnitudes.
Since David Boyd gives V=3D16.17, Ic=3D16.00, this is a blue object.
It could be a nova or perhaps a WZ Sge cataclysmic variable. At
minimum, it is an unusual object that is worthy of an IAUC.
Arne

----- Original Message -----=20
From: arne=20
To: Wolfgang Renz=20
Sent: Monday, August 22, 2005 5:47 PM
Subject: Re: New object near M27

Wolfgang Renz wrote:=20
I just asked about the galaxies because the next one ist just 2.5
arcmin away.

Faint galaxy usually means distant or at least small, so 2.5 arcmin
means many tidal radii from the center and so therefore the new
object is highly unlikely to be a supernova within that galaxy.
(Nice idea, tho)
Arne