The goal of this course is to introduce students to the very wide range of methods by which astronomers can measure the properties of objects beyond the Earth's atmosphere. This is a survey course, meaning that we will touch on many topics, but cover very few -- perhaps none -- in much depth.
One might describe the course as focusing on several closely related issues:
Q: How many "messengers" can you name?
Q: What sort of sources are the most likely candidates for each type of messenger? (Just for fun now)
My plan is to touch lightly on most types of detector, in part because our time is limited, but also in part because I'm certainly no expert in most of them. We will go into a bit of detail on optical detectors, simply because they are used widely to study all sorts of objects, and because I know something about them.
In addition, for a subset of our regimes, I'll try to describe some of the data reduction techniques. This is not the right course to take if you are interested in gaining a working knowledge of, say, optical CCD-based photometry, but it will at least introduce some ideas and basic concepts.
Let's look at an event which has been in the news recently -- it can show the importance of multi-messenger astronomy. You've probably heard about it.
Perhaps the best way to start our discussion is with a simple timeline:
|2017 Aug 17 12:41:06||Fermi satellite||detects a short gamma-ray burst|
|2017 Aug 18 10:25 (??)||J. Craig Wheeler announces a LIGO source with optical counterpart|
|2017 Aug 18 00:04||CTIO 4-m DEC||starts observing a location in the sky at RA = 197.13, Dec = -23.33|
|2017 Aug 18 22:56||ALMA||starts observing a target at RA = 13:09:48, Dec = -23:22|
|2017 Aug 19 17:09||Chandra satellite||starts a 25-kilosecond exposure at RA = 13:09:48, Dec = -23:22:53|
|2017 Aug 21 10:53||HST||starts observations under at least 4 different proposals for target-of-opportunity "GRB 170817A" RA = 13:09:48, Dec = -23:22:53.2|
You can find a more detailed discussion of this event in one of the later lectures
Q: Just how close are the positions of the gamma-ray burst and the optical counterpart? What is the expected uncertainty in position for the gamma-ray burst? Q: Who are the scientists who have been given time to chase this object with HST? Q: Did the Chandra satellite detect anything?
The one type of information which we DON'T have, at the moment, is exactly where and when the LIGO and/or VIRGO teams detected gravatational waves. And we may not have that information for some time.
(I am following many leads which appear on a blog entry for Telescoper).
Well, well, well.
Q: Just what might be present in the sky at the position to which these telescopes were pointing? RA = 13:09:48 = 197.45 Dec = -23:22:53 = -23.38
There are many good tools to answer that question. A few of my favorites are:
Q: What about neutrinos? Where was the IceCube observatory looking over the past week?
Copyright © Michael Richmond. This work is licensed under a Creative Commons License.