Gamma ray burst
28 Nov 2006 14:59:08 UTC
Topic 192131
(moderation:
Here is an interesting object:
GRB
However I cannot find it in grb.sonoma.edu, which shows a real time map of recent GRBs.
Tullio
Gamma ray burst
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Thanks for pointing this out! I found this on an ESA page:
Regards,
Bert
Somnio ergo sum
RE: Thanks for pointing
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Thanks. Funny thing, grb.sonoma.edu reports an Integral observation on September 12, not September 17 like ESA says. And it does not look like the same object. But these GRBs are a real mistery.
Tullio
RE: Thanks. Funny thing,
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I'm guessing the radiation from the source wasn't "hard" enough to qualify as a GRB, as it's been termed an X-ray nova event... I've also noticed it can take a few days, after a burst has been analyzed with evaluation of the light curve, before the description will be available at the grb.sonoma.edu GRB Real-time Sky Map. Exciting nevertheless... I'm wondering what kind of star got swallowed, specifically, was it a neutron star? If so, that's one of the types of mergers that the LIGOs may be able to detect...
Thanks for pointing out the ESA page, Bert! I started searching the NASA's HEASARC: Archive, and went from there to Search of INTEGRAL Catalogs, trying to identify the picture in the article with all the images available from the links. It's awesome how you can enter coordinates, or an object's name, and then get images from the various astronomical databases that pertain to that location or object!
RE: […] It's awesome how
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A couple of sites I refer to often are Simbad and VizieR.
RE: RE: […] It's
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Thanks Odysseus,
I was astonished to see that over 2000 objects were retrieved when I tried a query of M31 (and anything else within 10'). About how much area of the sky does that cover, compared to, say, a disc the size of a full moon?
What do you look usually look for? A specific type of source (e.g., x-ray, optical, or IR) in particular?
Are you, by any chance, familiar with the 'fv' program, or the other software mentioned here?
RE: I was astonished to see
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The Andromeda Galaxy covers much more, depending on the size of one’s telescope and the viewing conditions. A disc the size of the Sun or Moon (half a degree in diameter) is somewhat larger than the galaxy’s central core (which can easily be seen with binoculars, under decent conditions), but considerably smaller than the shortest diameter of the object as usually seen through amateur ’scopes, an ellipse of roughly 45' by 2°. Sensitive photography shows M31 to extend more than four or five degrees in the direction of its longest diameter.
But a circle ten arc-minutes in radius covers less than half the area of the Moon’s disc.
I imagine quite a few of the objects that would show up in a listing from that immediate neighbourhood are star clusters, Cepheids, &c. belonging to M31 rather than our own Galaxy.
Most often optical: specific stars or DSOs that I’ve been reading about or that have been mentioned or had their images posted on newsgroups (alt.binaries.pictures.astro is one of those I read regularly).
No, I haven’t had much to do with FITS images and so on. I downloaded fv a while ago just in case it would come in handy, but haven’t had occasion to actually run it yet.
Thanks Odysseus! Of
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Thanks Odysseus!
Of course, I recall reading recently that Andromeda is bigger (or has more mass) than our Milky Way, but I had no idea that the "actual size" of it in the sky was that large.
Knowing that the Moon is a half a degree in diameter is a big help. Much obliged for the reference :)
RE: Of course, I recall
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Yes, it’s quite astonishing in perspective. Unfortunately it can be a rather unsatisfying object to observe visually; it more than fills the FOV of most telescopes large enough to pick up the fainter parts, so there’s little contrast to work with. Still, you can make out some of the dark, dusty regions that delineate the spiral arms.
That said, M31 is probably the most distant object you can expect to see with the naked eye under any reasonably dark skies; the central core can usually be detected once you know where to look. Excellent conditions will allow the brightest part of the disc to be seen with binoculars. Moreover its high declination makes it available for much of the year to observers in the Northern Hemisphere, its evening ‘prime time’ coming in late summer. I’ve often glanced up at it and marvelled that those photons being captured by my retina were emitted when the earliest members of genus Homo were venturing out of the African forests …
I've been busy playing around
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I've been busy playing around with the Aladin Sky Atlas (using Simbad and VizieR), trying to get a better idea of where in the sky IGR J17497 -2821 (the event mentioned in the original post) occurred. I still have much to learn about Astronomy, and also about using the interactive sky atlas... so if these images are at all appealing, the credit goes to the countless individuals who've worked hard and long to collect and compile all the different data, and to those at the CDS who have developed such a marvelous tool like Aladin, that allows an amateur like me to generate pictures like these:
(click the thumbnail for the full-sized image)
The reticle shows the location of the center of our Milky Way Galaxy, and the arrow shows where IGR 17497-2821 happened. I selected three different plates (that came from Aladin's database of digitized photographic plates, such as DSS-I, MAMA, or DSS-II) to make these RGB images:
Red: PI-SERC.J.MAMA.455-PLATE,
Green: PI-SERC.I.MAMA.455-PLATE, and
Blue: PI-SERC.S.MAMA.455-PLATE.
The contrast for all 3 colors was adjusted up (clicking the 'Pixel' button, and sliding the middle triangle-pointer to the left), but by about only half as much for the blue, than as for the red and green.
When the light that struck the photographic plates for these images first started its journey, the Neanderthals were dying out, leaving Homo sapiens and Homo florensiensis as the only living species of the genus Homo. Humans were already weaving fabric, and pressing the patterns into clay before firing it into pottery. And, they were already skilled with basic aspects of gravity and flying things, at least insofar as projectiles used for hunting are concerned...
@ Odysseus: it looks familiar, but I have to ask, what's the image for your avatar?
@ Mike: great to have you back at the helm of the Detector Watch thread; I've been checking every pixel of Justin's pics of ETMy; I'm still looking for an 'illustrated parts breakdown' or exploded view to help identify everything; specifically, are there grooves in the optic that the suspension wires ride in? Also, since the above image covers only a 6-degree by 6-degree swath of the sky, I'm not only anxious to see what else I've been missing (I don't even have a pair of binoculars!), but I think I might be able to make an animated gif that will use the light curve data from IGR J17497-2821 to show what it looked like in the above image (in sort of time-lapse and proper 'false' colors of course; can't believe how much I need to learn still! :) )
RE: @ Odysseus: it looks
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A Hubble image of the “Homunculus�, a bipolar plume of ejecta from Eta Carinae, in the heart of the great Carina nebula, NGC 3372. In the XIX century this gigantic star underwent a peculiarly violent outburst lasting several years; for a while it may have been the brightest single object in the Galaxy. Astronomers have been watching the cloud expand for the past fifty years or so.