Pinkish object (star?) at 8 o'clock in the Skyserver image
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Abe_Hoekstra
Is the object a transient, or a glitch (cosmic ray hit)?
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Abe_Hoekstra
Looks like it is visible here too.
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Rick_Nowell
The pinkish spot is not visible in SDSS DR7, but it is visible in DR8.The top SDSS photo in this thread is DR9.
http://cas.sdss.org/dr7/en/tools/explore/obj.asp?id=587729777980866758 (DR7)
http://cas.sdss.org/dr8/en/tools/explore/obj.asp?id=1237655499205771446 (DR8)
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Abe_Hoekstra
Hi Rick, is this a transient object or a glitch (cosmic ray hit)?
I checked DR 10 - 12 and the "star"is still visible. Is it the same image for data release 8 - 12?Posted
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Abe_Hoekstra
I checked the date for DR 6 - 12, and unless I made a mistake (could be, I am new to finding that kind of info), the date for all of the images is 05-24-2001.
How is that possible as the pinkish feature is not visible in DR 6 -7 , but is in DR 8 - 12?Posted
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Abe_Hoekstra
Sky View
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Rick_Nowell
It is not visible in DECaLS DR5.
BUT, if you go to the DECaLS DR5 page from this link,
http://legacysurvey.org/viewer?ra=213.78632&dec= -1.81109&zoom=16&layer=decals-dr5
and then from the right hand panel tick SDSS images, the Pinkish object CAN be seen. Make of that what you will. It's not a foreground star in our galaxy otherwise it would show in all the images.
My understanding is that all the SDSS photos were done prior to 2009 when the imaging camera was retired. Most for DR7, which is SDSS-II, were done in 2001 but some were also done after that. It is hard to say without an expert when the images were taken...
THE SEVENTH DATA RELEASE OF THE SLOAN DIGITAL SKY SURVEY
https://arxiv.org/pdf/0812.0649v2.pdfAs for whether it is a transient event, like a supernova, I can't say.
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Abe_Hoekstra
Thank you for looking into it, Rick.
I will post it in objects that need more research.
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Rick_Nowell
I zoomed in as far as SDSS would let me and got to this, perhaps a few pink pixels. Address below.
http://cas.sdss.org/dr8/en/tools/chart/navi.asp?ra=213.78632114&dec=-1.81109337 near Objid 1237655499205771446
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c_cld
Your area ra , dec 213.789 -1.812 was imaged on run 2334 , run 6751 and run 6782 as seen in frames
https://dr12.sdss.org/sas/dr12/boss/photoObj/frames/301/2334/4/frame-irg-002334-4-0120.jpg no transient
https://dr12.sdss.org/sas/dr12/boss/photoObj/frames/301/6751/2/frame-irg-006751-2-0146.jpg no transient
https://dr12.sdss.org/sas/dr12/boss/photoObj/frames/301/6782/2/frame-irg-006782-2-0068.jpg with transient
The last frame was shot on mjd_r = 54205.2626082901 i.e. 2007-04-15 06:18:09.356 UTC
see host http://skyserver.sdss.org/DR14/en/tools/explore/summary.aspx?id=1237674602143154460 from run 6782 to get date/time of the frame (click 'field' on left column of 'explore page' )
No need to report a 10 years old possible supernova as there is no spectrum available 😦
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Abe_Hoekstra
Hi c__cld, I know there is little scientific value to these objects from years past, but I love looking for them. I hope to find a few more.
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Ghost_Sheep_SWR
in response to c_cld's comment.
I disagree, you never know when some data / information point might be useful in the future.
For instance if a new SN goes off at the exact location, an entry as transient might give rise to further research into a possible supernova imposter. Or perhaps in the future there will be a team dedicated to attempting to classify unclassified reported transients based on archival photometry etc.
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But anyway, I see a squarish thing only in i band (Aladin Desktop) so I'm pretty sure it's an artifact / cosmic ray hit.
If IRSA Finder Chart would be functioning normally I would've probably been able to show you, but 😕
For doing some research yourself here's a primer;
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Budgieye
moderator
IRSA Finder wouldn't have enough resolution to look at this. Cosmic ray hit sounds good. EDIT I was just wondering if it was a red dwarf star moving quickly. Can't see that it is.
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Rick_Nowell
Just for asking, but if a supernova produced a Gamma-ray burst (GRB) because it was particularly intense, then that would produce many different types of cosmic particles and rays. Can the 'cosmic ray' hit above include those that would have been produced by, say, a GRB within the galaxy? When looking at the above galaxy, does it have to be either/or? Yes there was an intense supernova that produced lots of cosmic particles, rays and hits, which is what we're seeing. One might not exclude the other.
https://en.wikipedia.org/wiki/Gamma-ray_burst
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AFAIK the position / direction from which a Cosmic Ray Hit hits a CCD has nothing to do in general with the apparent position in the resulting image.
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c_cld
For any survey (SDSS, GAMA, etc...) one can ruled out cosmic ray hits, but not "bad CCD pixels" when you see a blob in multiple filters or composite frames at different times.
Here it's the case for two gri composite frames during the drifting run 6782:
https://dr12.sdss.org/sas/dr12/boss/photoObj/frames/301/6782/2/frame-irg-006782-2-0068.jpg
and
https://dr12.sdss.org/sas/dr12/boss/photoObj/frames/301/6782/2/frame-irg-006782-2-0069.jpg
I second Ghost_Sheep_SWR for an artifact after downloading fits files of filters images and jpg files link in Aladin.
https://dr12.sdss.org/sas/dr12/boss/photoObj/frames/301/6782/2/frame-i-006782-2-0068.fits.bz2 and other filters r,z / run 0069
Hope this help your analysis. 😃
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Rick_Nowell
So either an unproven transient object like a supernova or an imaging anomaly. Cosmic ray hit is an imprecise description; after all, light is a ray from the Cosmos.
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Ghost_Sheep_SWR
in response to Rick_Nowell's comment.
In the case of regular cosmic rays that create CCD artifacts it's particles, leftover name from the past;
https://en.wikipedia.org/wiki/Cosmic_ray
https://www.eso.org/~ohainaut/ccd/CCD_artifacts.html
Real transient event seems unlikely because of the sharp shape, 1 band only appearance.
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