Starship Asterisk*

I don't know if anyone here knows anything about this, but I figured I'd post it anyway. I don't sit and look at raw, uncombined, level 1 data in the archive too often, but I have looked at it enough to know this is at least a little unusual. Typically, in single exposures, cosmic rays have a random distribution across the field. Last night, this caught my attention because it's clearly not random and I'm not sure what happened. Maybe it's not cosmic rays but it sure does look like a bunch of them. They clumped in the right corner but there are more in the overall field too. Unfortunately, I'm coming up empty handed trying to search for any explanation. It's probably out there and I'm just not using the right search terms.

1.3 Mb png
http://www.geckzilla.com/astro/proxima_centauri_CRs.png

I'm probably asking seriously dumb questions, geck, but can you explain some more for an outsider to image processing?

Where are the images from (as in, who took them, the Hubble space telescope)? And - When?

M

Oh, yeah, sorry. These are some old Hubble WFPC2 images of Proxima Centauri taken in 1995. 1995-08-13 at around 19:40 to be more precise.

geckzilla wrote:Oh, yeah, sorry. These are some old Hubble WFPC2 images of Proxima Centauri taken in 1995. 1995-08-13 at around 19:40 to be more precise.

OK. And what is the field of view? How far away from Proxima Centauri is that scatter of ¿cosmic rays? ?
This is most unlikely to be relevant, but I came across this paper from 1998 which suggests a faint companion to Proxima Cent within what I think reads as 0".5 and possibly means one half an arc second. (Later research gives a no vote to the existence of a companion.)

But, in any case, that scatter in the top right corner didn't look like it could have originated from a single, dim, point source.

My only and unverifiable guess would be that an AGN in that direction had emitted a burst of energy that reached the Hubble detectors on 1995-08-13...

M

I was thinking it might be related to solar activity but can't explain how the particles would get from the Sun to Hubble's detector since Hubble always points well away from the Sun.

Could it be related to variations in Earth's magnetic field?

Could it have anything whatsoever to do with the fact that Proxima Centauri is a confirmed flare star?

Ann

geckzilla wrote:I don't know if anyone here knows anything about this, but I figured I'd post it anyway. I don't sit and look at raw, uncombined, level 1 data in the archive too often, but I have looked at it enough to know this is at least a little unusual. Typically, in single exposures, cosmic rays have a random distribution across the field. Last night, this caught my attention because it's clearly not random and I'm not sure what happened. Maybe it's not cosmic rays but it sure does look like a bunch of them. They clumped in the right corner but there are more in the overall field too. Unfortunately, I'm coming up empty handed trying to search for any explanation. It's probably out there and I'm just not using the right search terms.

Actual cosmic ray hits on the detector are somewhat rare. Usually, what we call a cosmic ray hit is actually the result of one or more secondary particles produced when a cosmic ray strikes some other part of the camera or telescope structure. A really high energy cosmic ray can produce an impressive shower of secondary particles, and if the structure that is hit lies fairly close to the detector, I imagine the data might look like the example you've found.

Oh, I didn't know that they were usually secondary particles. That's probably a lot better as far as the integrity of the CCD goes.

As a side note, I was downloading raw data in order to make this picture.

Mais il est une très belle photo d'une étoile.

Yeah, the original pipe image had a slightly different meaning from mine. The Treachery of Images got me thinking about how confused people sometimes are by astronomical imagery. So confused are some people that they think the white circle in the middle is the body of the star itself. So I say it's not a star. It's a point spread function!

geckzilla wrote:Yeah, the original pipe image had a slightly different meaning from mine. The Treachery of Images got me thinking about how confused people sometimes are by astronomical imagery. So confused are some people that they think the white circle in the middle is the body of the star itself. So I say it's not a star. It's a point spread function!

Well, it's a très joli point spread function then! (Zooming in on the psf centre makes an extremely joli(e) image.)
M

Il est pas une fonction d'étalement de point. Il est une représentation graphique d'une fonction d'étalement de point.

(I like it more if I consider it to have the same meaning as Margritte's original. Ze artist does not dictate ze meaning.)

I really like the level of cultural sophistication here - and thanks for the explanations, Chris and Geck!

Ann

Nitpicker wrote:(I like it more if I consider it to have the same meaning as Margritte's original. Ze artist does not dictate ze meaning.)

Perhaps Magritte dictates its meaning. I would have to bow to his wisdom on this matter.

Edit: Apparently there is also an asteroid named after him. http://en.wikipedia.org/wiki/7933_Magritte

geckzilla wrote:

Nitpicker wrote:(I like it more if I consider it to have the same meaning as Margritte's original. Ze artist does not dictate ze meaning.)

Perhaps Magritte dictates its meaning. I would have to bow to his wisdom on this matter.

Edit: Apparently there is also an asteroid named after him. http://en.wikipedia.org/wiki/7933_Magritte

I assume the commonly held view of the original's meaning was also held by Margritte (I'm not sure). But an artwork doesn't need to have a universal meaning. Still, it appears I may have hurt your feelings, so sorry.

No, not at all. Not sure how I conveyed that.

I wasn't actually sure that you did convey that. I was just being overly cautious. I'm married to a very sensitive artist and I put my foot in it all the time.

I see. Well, maybe next time.