[vsnet-alert 13095] Re: DR UMa outburst!

[Tom Krajci]

I have done a quick examination of the stacked short-exposure BVRI images.

I compared instrumental magnitude of the target to GSC 3855-0825 (approx 
2 arcmin east of the target and approx. mag. 13.7)

It appears the B-V value for the target is about 0.2 mag brighter (i.e. 
less red) than GSC 3855-0825.

I would not put high confidence on these measures.  The target is faint 
and the exposures were short.  I am not experienced at multi-filter 
photometry reductions...I mostly operate scopes to collect the data.  
(If weather is good tonight I'll use longer exposures for BVRI coverage 
to improve SNR)

If anyone wants to examine the calibrated and stacked images, I would be 
happy to ftp them.

Tom Krajci
Cloudcroft, NM

======================================

On 4/5/2011 7:07 AM, Tom Krajci wrote:
> An all-night time-series of this object showed a steady brightening of 
> 0.3 mag.
>
> Casual visual inspection of the light curve may show faint hints of 
> shorter periodicities, but I leave that to formal analysis by others.
>
> I also took some short exposure BVRI images with a different 
> telescope.  I will see if stacking can make the target visible.  
> Perhaps these images will provide some useful color information?
>
> Tom Krajci
>
> ================================================================
>
> On 4/4/2011 9:51 PM, Brian Skiff wrote:
>> On Mon, 2011-04-04 at 20:37 -0600, Tom Krajci wrote:
>>> Initial unfiltered images from Astrokolkhoz (C11, 90 seconds) show an
>>> object at J2000  13 59 05.77 +55 44 29.49 at approx unfiltered mag 17.
>>>
>>> At the SIMBAD coords for DR UMa (13 59 05.4 +55 44 04) approx 25 arcsec
>>> away...nothing is detectable with a single image (fainter than mag 18?)
>>
>>       This links DR UMa with SDSS J135905.74+554429.3, whose
>> position is:  13 59 05.74 +55 44 29.4  (J2000).  The Sloan proper
>> motion is near zero.  The SDSS photometry is clearly for a very
>> blue object, which would seem to make the ID certain, and thus the
>> GCVS/VSX coordinates are in error.  No Sloan spectrum unfortunately.
>> SDSS r magnitude = 20.00, presumably at quiescence.
>>       Although the object is listed as a candidate quasar in various
>> papers, I see no redshift determination from a _spectrum_ in the
>> VizieR listing, only inference from colors and photometric redshift,
>> which is obviously wrong.
>>
>>
>> \Brian
>>
>