Radiation astronomy/First gamma-ray source in Scutum
The first gamma-ray source in Scutum is unknown.
The field of gamma-ray astronomy is the result of observations and theories about gamma-ray sources detected in the sky above.
But, gamma-rays from the Sun do not penetrate far enough into the Earth's atmosphere to be detected on the ground.
This is a lesson in map reading, coordinate matching, and researching. It is also a research project in the history of gamma-ray astronomy looking for the first astronomical gamma-ray source discovered in the constellation of Scutum.
Nearly all the background you need to participate and learn by doing you've probably already been introduced to at a secondary level and perhaps even a primary education level.
Some of the material and information is at the college or university level, and as you progress in finding gamma-ray sources, you'll run into concepts and experimental tests that are actual research.
The first step is to succeed in finding a gamma-ray source in Scutum.
Next, you'll need to determine the time stamp of its discovery and compare it with any that have already been discovered.
Over the history of gamma-ray astronomy a number of sources have been found, many as point sources in the night sky. These points are located on the celestial sphere using coordinate systems. Familiarity with these coordinate systems is not a prerequisite. Here the challenge is geometrical, astrophysical, and historical. The coordinates are usually supplied by the gamma-ray source observers.
A source of astronomical information on older detections of gamma-ray sources is included in the Science section of the lecture/article gamma-ray astronomy.
Traveling gamma-ray sourcesEdit
Many gamma-ray sources do not remain in a constellation for lengthy periods. Some of these are the Sun and sources apparently in orbit around the Sun. The Sun travels through the 13 constellations along the ecliptic (the plane of the Earth's orbit around the Sun): the 12 of the Zodiac and the constellation Ophiuchus. These are described in source astronomy.
To introduce yourself to some aspects of the challenge may I suggest reading the highlighted links mentioned above, and if you're curious, those listed under the section "See also" below.
Constellations change slowly with the precession of the Earth's orbital axes. This together with an objects relative motion may place it in one constellation in the past and a later one closer to the present.
The Wikipedia article about the constellation Scutum contains a high school level description. The upper figure on the right shows the sky map of Scutum. Around the edges of the map are coordinates related to longitude and latitude, but with the Earth rotating on its axis every 24 hours the celestial coordinates must remain fixed relative to the background light sources in the sky.
Also, in the Wikipedia article is a list of stars in Scutum.
In the lecture/article gamma-ray astronomy in its science section is a list of older catalogs of gamma-ray sources. Using the constellation description in the previous section and the range of coordinates for the constellation in source astronomy, scan through the coordinates for these gamma-ray sources to see if any may be within Scutum.
If you find any that are, skip down to the section gamma-ray source in Scutum and make an entry. Be sure to check the coordinate era, most B1950.0 coordinates have changed slightly to the new J2000.0 set. Try the catalog designation at either SIMBAD website.
Testing a sourceEdit
There are many web sites that may have a gamma-ray source listed for the constellation Scutum. Some that you may wish to try are in the External links section near the bottom of this lesson.
A. Constellation article
Under "Notable features" in the Wikipedia article on the constellation Scutum is the list of stars in Scutum. Click on this link. In the table of this Wikipedia article is α Sct. To the right are coordinates:
Right ascension (RA): 18h 35m 12.44s and Declination (Dec): -08° 14' 35.9". Find these coordinates on the Scutum map at the right.
To evaluate the star as a gamma-ray source, skip ahead to section "Gamma-ray source".
B. Wikipedia search
Another way to look for gamma-ray sources in the constellation is to perform a search on Wikipedia. Try "Scutum "gamma-ray"" without the outside quotes. This yields about 6 returns which include an outline of astronomy and a list of stars in Scutum.
To evaluate each of these as a gamma-ray source (or perhaps containing a gamma-ray source, try your browser's "Find" feature and enter gamma or gamma-ray), skip ahead to section "Gamma-ray source".
Another way to find possible gamma-ray sources in Scutum is to use search queries on SIMBAD.
Click on either SIMBAD link under "External links" below, then click on "Criteria query", or "by criteria".
In the tan box, type in "region(18 35 12.44 -08 14 35.9, 10m)", without the quotes. This tells the SIMBAD computer you are interested in a circular region of the celestial sphere centered on the coordinates for alpha Scutum, with a radius of 10 arcminutes (m).
Notice on the page over at the right from the tan colored box: "Return". The default is "object count". Click on "submit query". In a few moments a result something like "Number of objects: 4" should appear. Click "Back" to see the tan box again.
Add "otype='gam'", or "otype='gB'" for gamma-ray Burst, to the entry so that it reads: "region(18 35 12.44 -08 14 35.9, 10m) & otype='gam'", without the outside quotes. Click on "submit query" again. If the result is "0" number of objects, or "No object found", increase the number of arcminutes, or use "1d" which stands for "one degree".
When you find at least one object, change "Return" to "display" by clicking on the circle to its left, then "submit query".
SAO/NASA Astrophysics Data SystemEdit
In the naming of sources per constellation, the genitive is in common use. For Scutum, the genitive is Scuti.
Click on the SAO/NASA Astrophysics Data System link below in the "External links". Try "Scutum gamma-ray" without the quotes, or "alpha scuti" with quotes, followed by "gamma-ray" without quotes.
Click on a link below # Bibcode Authors. If the Abstract describes the detection of gamma-rays from a source in the constellation Scutum, go to the next section under "SAO/NASA Astrophysics Data System".
If it does not try another bibcode link.
There are several ways to evaluate a gamma-ray source for the constellation Scutum.
Click on the link to the Wikipedia article. After you've enjoyed reading about the source, use the 'find' command of your browser to see if this Wikipedia page mentions anything about "gamma-ray", or "gamma-rays". Does the article mention whether or not the source is a gamma-ray (γ-ray) source?
What is the current time stamp for the Wikipedia article on the source? [Hint]: look for something like "This page was last modified on 25 December 2011 at 20:12." very near the bottom of the page. For now this is an adequate time stamp.
From reading the Wikipedia article on the source, if you believe the text demonstrates that the source is not a gamma-ray source in Scutum edit the "Non-gamma-ray sources in Scutum" section near the bottom of the page with an entry similar to "# Alpha Scutum 25 December 2011 at 20:12 Wikipedia article "Alpha Scutum".", without the outer quotes, and finish the entry with four "~"s without the quotes after the period. The date included with your designation or username is a time stamp for the entry. The last portion of the entry is the source of your information.
On the other hand, if there are one or more sentences in the article that you believe demonstrates that the source is a gamma-ray source in Scutum edit the section below "Gamma-ray sources in Scutum" with a similar entry.
Go to the section entitled, "Challenging an entry".
To check any source (even one from Wikipedia) on SIMBAD, click of the "External link" to the "SIMBAD Astronomical Database".
At the lower right side of the SIMBAD Astronomical Database page is a "Basic search" box. There are several ways to try your target:
- source name: without the quotes or
- source coordinates: without the quotes, for example, "18 35 12.44 -08 14 35.9".
If you are looking at a SIMBAD generated table which lists possible targets, click on one.
On its SIMBAD page read down the left side until you see "Other object types:". To the right of this is a list of other object types that the source is. Look for a gam or gB. Is there one in this horizontal list?
If a gam or gB is present, skip down to the section, "SIMBAD time stamp". Even if a either is not present, noting that SIMBAD does not consider the source to be a gamma-ray source is important, so skip down to the "SIMBAD time stamp" section.
If you have already found a gamma-ray source (or a table of them) using SIMBAD, click on the blue link identifier for the first.
SIMBAD time stampEdit
Peruse the SIMBAD page for a time stamp or date of last revision. [Hint: it may look something like "2012.01.09CET20:10:02" and be in the upper right.]
If the entry at SIMBAD convinces you that the source is not a gamma-ray source, edit the "Non-gamma-ray sources in Scutum" section near the bottom of this page and type in an entry similar to "# Source Name 2012.01.09CET20:10:02 SIMBAD article "SIMBAD source name".", without the first set of quotes, followed by four ~s.
If your SIMBAD analysis convinces you that you have found a gamma-ray source in Scutum (did you check the coordinates vs. the map of Scutum?), make an entry something like the ones in the section "Gamma-ray sources in Scutum".
SAO/NASA Astrophysics Data System sourcesEdit
If the abstract states that a gamma-ray source in Scutum is detected or studied, consider entering it in the section "Gamma-ray sources in Scutum" below.
Abstract time stampEdit
On the abstract page is a Publication Date:. This may serve as a time stamp for establishing that the source is detected as a gamma-ray source on or before the date of publication. The time stamp followed by four ~s for your verification as determiner in the section "Gamma-ray sources in Scutum" completes your entry.
Challenging an entryEdit
Any entry in either the section "Gamma-ray sources in Scutum" or "Non-gamma-ray sources in Scutum" can be challenged. The time stamp can be challenged to see if there is an earlier one. The source can be challenged by an earlier source.
Is Wikipedia a 'primary source', or does the Wikipedia article cite a source?
Even though Wikipedia has an article on the source, is it a good place to stop in testing whether the source has been detected as an astronomical gamma-ray source?
If the Wikipedia article cites a primary source, skip down to the section on "Primary sources".
Is SIMBAD a 'primary source'?
SIMBAD is an astronomical database provided by the Centre de Données astronomiques de Strasbourg. It is an authoritative source, but they do occasionally make a mistake.
If you find a gamma-ray source within the constellation on SIMBAD, the next step is to find the earliest time stamp of discovery.
SAO/NASA Astrophysics Data System challengeEdit
Is the SAO/NASA Astrophysics Data System abstract entry a primary source?
The SAO/NASA Astrophysics Data System is an astronomical database provided by the High Energy Astrophysics Division at the Harvard-Smithsonian Center for Astrophysics of Harvard University. The abstract has been copied from the actual article in a scientific journal or other publication. Mistakes can be made and the article may record within its text exact dates when the observation or detection of gamma-rays actually occurred. Such a record may provide an earlier time stamp.
Primary sources may be searched for possible additional information perhaps not yet evaluated by SIMBAD or not presented in a Wikipedia article about a source.
Wikipedia test sourcesEdit
For a Wikipedia article that cites a primary source, scroll down to the reference and open the reference. Read through the article looking for where the source mentioned in the Wikipedia article occurs. Some primary source authors may use source designations that are not mentioned in the Wikipedia article. To look for other designations, click on the link to SIMBAD in the "External links" on this page, enter the source name from the Wikipedia article, and see if other names are mentioned in the article.
When none of the names are mentioned, click on the link for "Google Advanced Search" in the list of "External links", enter the source name or designation(s) such as "Gliese 866", with "gamma-ray" to see if the source has a reference indicating it is a gamma-ray source. And, look for the earliest one. Compose an entry using the primary source.
SIMBAD test sourcesEdit
Further down the SIMBAD page is a list of "Identifiers". Click on the blue bold portion.
On the page that appears should be a primary source listed after Ref:. Click on the blue link with the oldest year. This yields an earlier time stamp and entry citation like the current one in the section "Gamma-ray sources in Scutum". If you find another source or an earlier time stamp, compose a similar entry and edit the section. Additional information to add into the reference can be found by clicking on "ADS services" from the SIMBAD page.
SAO/NASA Astrophysics Data System sources testEdit
Click on either the "Electronic Refereed Journal Article (HTML)" or "Full Refereed Journal Article (PDF/Postscript)", if available.
Depending on the article display, if the abstract is repeated and the article is listed as FREE, click on either the PDF or HTML version.
While scanning or reading the article look for "Observations" (or use the Find function of your browser) and the possible inclusion of dates for these. If more than one gamma-ray source in Scutum are detected, which one(s) would you list in the section "Gamma-ray sources in Scutum" below?
An example of an article reference is provided in that section.
Changing an entryEdit
From your analysis of the source so far, is it a gamma-ray source?
If you have found an earlier time stamp for the source than the one listed in the section below "Non-gamma-ray sources in Scutum" and the answer to the above question is "no", you can edit the section with your result. Or, you can leave the entries as is and try another star.
If you have found an earlier time stamp for the source than the one listed in the section below "Gamma-ray sources in Scutum", edit the section with your result. Or, if you found another gamma-ray source with a comparable or earlier time stamp, edit the section with your result.
Gamma-ray sources in ScutumEdit
- LS 5039 in Wikipedia is a high-mass X-ray binary; microquasar; and gamma-ray emitter at J2000 18h 26m 15.06s -14° 50' 54.3". It was discovered --Marshallsumter (discuss • contribs) 00:00, 3 February 2015 (UTC)
- PSR B1828-11 in Wikipedia is a gamma-ray emitting pulsar J1830−1059, scanned before December 16, 2008. --Marshallsumter (discuss • contribs) 01:49, 3 February 2015 (UTC)
Non-gamma-ray sources in ScutumEdit
For any particular source, the SIMBAD record may indicate that it is not a gamma-ray source yet above you may have found at least two refereed journal articles indicate that it is. Use the second SIMBAD External links to directly display the SIMBAD database in France.
Enter the name source you have found into the search box. Scroll down to the Annotations :. Look for the link "add an annotation to this object". With browser open to the literature citations available, click on this link. You may need to register as a user. It's free. Post your annotation containing the literature references.
- The first gamma-ray source in Scutum is a galaxy.
- Voges, W.; Aschenbach, B.; Boller, Th.; Bräuninger, H.; Briel, U.; Burkert, W.; Dennerl, K.; Englhauser, J.; Gruber, R.; Haberl, F.; Hartner, G.; Hasinger, G.; Kürster, M.; Pfeffermann, E.; Pietsch, W.; Predehl, P.; Rosso, C.; Schmitt, J. H. M. M.; Trümper, J.; Zimmermann, H. U. (September 1999). "The ROSAT all-sky survey bright source catalogue". Astronomy and Astrophysics 349 (9): 389-405.
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