Arne's List of Projects

I would be interested in the project p007.sdssphot.txt, which describes needing a volunteer for different tasks involving preparing a paper. As long as I have good instruction (I don't have any experience in some of these things, but am great at following directions), I would love to help out. I could also help with some of the data mining projects like p064.v838monfield.txt, again with good instruction. Cheers, Chase

Hi Chase! the sdss photometry project is a big one, involving some 200 nights of data with the USNO 1.0m telescope. I produced a poster for a CV conference based on the initial processing, but for a publishable result, I need help in doing a decent literature search. Some of these stars were discovered nearly a decade ago, and have had outbursts since then. I haven't stayed current with the literature, and so seeing what others have learned is essential when writing a new paper. Someone also has to take the raw lists of photometry and make some pretty light curves for publication. Probably the way to start is with a subset of the entire list. Let me give you a dozen stars and see what you can find out about them...it will take me a day or so to get set up. Arne

Hi Arne! Thanks for letting me help you out with this project. You're probably right about the subset idea. Idon't want to get in over my head, but I am excited to dive in. Iwent ahead and found the two papers cited in your notes; I'll read them tonight to get the lay of the land. Cheers, Chase

Hi Chase, Given below is a list of 10 SDSS CVs to start with. The "object" name is the SDSS "plate" and "fiber" for the spectrum associated with the particular object. The RA and Dec can be used to create the approved SDSS name, as in SDSS Jhhmmss.ss+ddmmss.s On the same line as the object name is 1-3 dates in the format 04d260, which is 2004 day 260. Underneath each first line is the time series photometry, listed one night per line, with a date followed by the hours that I monitored the object (0546-1227 means from 05:46 to 12:27 UT). If I knew a GCVS name for the object, it shows up on the first line in brackets. The generic V magnitude for the object in the SDSS catalog is also given (it is usually the quiescent magnitude). There may be additional notes. The first step is to find these objects in Simbad (http://simbad.u-strasbg.fr/simbad/). See if they have been given GCVS names (I think the first two papers might have made it into a GCVS namelist). Then look at the references section and see if a paper has been written that includes the CV, perhaps with additional information. Of course, the SDSS paper will appear there (the place in the 6-paper series is shown by the letter after the plate/fiber object name; for example, p1468f163d is in paper 4). Next is to check VSNET and CVNET to see if outbursts have been detected, and if so, record the outburst date and any ancillary information (like the peak magnitude, superhump period if seen, etc.). In other words, maybe start a page or spreadsheet for each object and record as much information and references for them as possible. There are lots of objects, so this will be a lot of work - but you get to look at some interesting stars along the way! The CVNET archive is at https://sites.google.com/site/aavsocvsection/Home and you may have to join the google group. Likewise, its maillist archives are kept in yahoogroups, so you will probably have to join them too. VSNET alert, which is the most useful of the VSNET mail-lists, has an archive at http://ooruri.kusastro.kyoto-u.ac.jp/pipermail/vsnet-alert/. You might also go to the SDSS web site http://www.sdss.org/, work your way through, and look at the spectra of each of these. They are really neat objects with emission lines and sometimes the signature of the donor star at the red end of the spectrum. A smaller version of each spectrum can also be found in the SDSS CV series paper. That will get you started. Most of research is like this - checking to see the history of the object or subject that you are studying! Again, if others want to join this project, they are more than welcome. I'm giving detail on this one because it is complex; most of the other Arne's Stars are much simpler projects. Arne ----------------------------- Object RA Dec V Dates (paren=monitor hours) p1468f163d 00:18:56.93 +34:54:44.3 04d260 04d269(0546-1227) heII; P~18min p1913f544e 00:26:03.80 -09:30:21.0 20 nl? 05d359(0154-0534) p1493f204d 00:27:28.01 -01:08:28.5 20.6 04d260 [EN Cet] 04d235(0734-1146) p690f568d 00:39:41.07 +00:54:27.6 20.7 04d260 04d236(0653-1205) FAINT >320s p1085f175c 00:43:35.14 -00:37:29.8 18 04d018 04d260 03d322(0211-0829) ec? 4min P=78m p1496f493d 00:50:50.88 +00:09:12.7 20.4 04d018 04d029 04d260 03d325(0140-0826) 5min ASAS outburst 2257.86163 11.526? p2062f22g 01:29:40 +38:42:10 19.8 05d360(0122-0700) p662f384b 01:31:32.39 -09:01:22.3 18.5 02d018x 02d038 02d348(0216-0622) full moon 02d361(0151-0627) P=98m ASAS 1pt 2300 13.5 p662f552b 01:37:01.06 -09:12:35.0 18.8 03d003 03d008 03d012x 02d360(0153-0648) P=83m ASAS 3 outbursts to 12.5 spaced 500d p430f430a 01:51:51.87 +14:00:47.2 20.5 01d201 01d236 02d036 02d362(0157-0728) high incl.

Hokay! I've started going through SIMBAD and finding all the references through there. Not all the papers are available for free on the internet, so I'll have to check with the University library and see if either they have copies of them, or else try and get them via interlibrary loan. Fortunately, all the SDSSCV papers are available in PDF. A note: object *p690f568d* does not seem to be in SIMBAD. Is it possible that the RA and Dec numbers you listed are inaccurate? This is fun. I haven't had an interesting research project since my senior thesis. I'm really going to enjoy the process of making this into something publishable. Cheers, Chase

Hi Chase, Several emailers were nice enough to remind me that there is another excellent resource that you should tap: VSX. I wasn't aware of how much work Patrick Wils had put in on these CVs; if you look at the reference links, he includes most of the recent papers on each star. I'd start there, and then branch to some of the other resources I mentioned. http://www.aavso.org/vsx The references are relatively complete for recent papers, but it pays to check Simbad too and see if papers were missed. Arne

Hi Arne! Thanks to John for suggesting the VSX. I had glanced at it before, but didn't realize that it also had refereces listed as well. It is interesting that VSX and SIMBAD seem to share some but not all the same references for each star (at least in the first couple I've glanced at). More stuff to compare is better, yes? So, Ispent some time and compiled a list of all the reference papers given for each object in both SIMBAD and VSX. Many of them seem only to be lists of objects, or else papers detailing updates to databases of objects. So I decided to rate them all as low, middle, or high priority based on their abstracts. Low priority are the list-of-objects type papers. High priority are papers specifically dealing with some kind of observation or theory concerning our stars. Also, I marked all the original SDSSCVpapers as high priority. Middle priority are those that may deal with a related subject but not directly refer to our stars, or else are unclear and need to be checked, but not first. Would you like me to post this list, or would you rather wait till I can read the papers and simply post the interesting information? Cheers, Chase. P.S.: Two of the stars you listed are not found in either SIMBAD or VSX: *p690f568d* and *p2062f22g*. Could this be due to typos or are they simply absent from these databases? --C

Hi Chase, I'm going to give a couple of posts regarding my original thoughts about this project. It started with an SDSS collaboration, led by Paula Szkody, to study the new objects found by SDSS that had spectra that looked like cataclysmic variables. I had a 1-meter telescope available to me most of the time, and it made sense for me to spend small-telescope time to do an initial investigation, see if eclipses or other structure were present that could give an indication of period, inclination, variability type, etc. I then passed that information to Paula, and she used the APO 3.5m telescope to acquire phase-covered spectra of the objects. In many cases, my photometry then was included in the paper. So a good starting point on a project like this is to read at least the first paper of the series (where much of the observational techniques are covered), and if possible, all of the papers. You get to see some of the light curves and a lot of spectra, giving you a good background for what we were trying to accomplish. Now, not all time series were included in the papers, and we've taken additional data since then. The question is how to best use the data to further science. The simplest way is to just publish the observations, with little or no analysis. The next level is to see what we have that others don't, and what kind of questions could be answered with that dataset. Certainly the original papers have no information about outburst history, since that history has happened since the publication of the paper. Statistics of this nearly complete sample, use of the B&V calibrations, looking at the nearby stars, etc. are all areas that can be explored. So first, study the original CV paper series, and then we'll go from there. Arne

Hi Chase, I'm going to give a couple of posts regarding my original thoughts about this project. It started with an SDSS collaboration, led by Paula Szkody, to study the new objects found by SDSS that had spectra that looked like cataclysmic variables. I had a 1-meter telescope available to me most of the time, and it made sense for me to spend small-telescope time to do an initial investigation, see if eclipses or other structure were present that could give an indication of period, inclination, variability type, etc. I then passed that information to Paula, and she used the APO 3.5m telescope to acquire phase-covered spectra of the objects. In many cases, my photometry then was included in the paper. So a good starting point on a project like this is to read at least the first paper of the series (where much of the observational techniques are covered), and if possible, all of the papers. You get to see some of the light curves and a lot of spectra, giving you a good background for what we were trying to accomplish. Now, not all time series were included in the papers, and we've taken additional data since then. The question is how to best use the data to further science. The simplest way is to just publish the observations, with little or no analysis. The next level is to see what we have that others don't, and what kind of questions could be answered with that dataset. Certainly the original papers have no information about outburst history, since that history has happened since the publication of the paper. Statistics of this nearly complete sample, use of the B&V calibrations, looking at the nearby stars, etc. are all areas that can be explored. So first, study the original CV paper series, and then we'll go from there. Regarding whether stars are missing from Simbad or VSX: look at the papers from which those stars were taken, and compare coordinates there. It could be that I've mistyped something. Arne

Hi Arne! Sorry for not getting back to you sooner - I've been snowed in, out of town for the weekend. However, that just means I've had plenty of time to read and research! I've studied the first two SDSSCV papers, so I have learned some things about three of the assigned objects, p430f430a (SDSS 0151), p662f384b (SDSS 0131), and p662f552b (SDSS0137). SDSS 0151 was found in the first year of SDSS. According to the paper, the spectra observed during the survey contain deep central absorption in the Balmer emission lines, which indicates that the system is high inclination (as also you pointed out in your notes), and likely eclipsing. The spectra are postulated to be caused by outer disk material that is cool, low velocity, and in the line of sight. This needs confirmation by follow-up observation of an eclipse or outburst. SDSS 0131 and SDSS 0137, from the second survey year, both appear to be systems with a low mass transfer rate. This is indicated by the fact that the spectra of the underlying stars is observable - meaning that the radiation from the system isn't dominated radiation from the accretion disc - meaning it probably doesn't have a significant accretion disc - meaning little mass has transferred from the secondary to the primary. In addition to this, the TiO spectra of the white dwarf is apparently evident in SDSS0137. Follow-up spectral observations reveal a very short period (1.4hrs) and a high-amplitude velocity curve, consistent with a high inclination (which would also need to be confirmed observationally during eclipse or outburst). (Note: Ihave two more papers concerning SDSS 0131 in PDF, so Ican read those immediately after finishing the rest of the CVseries, but the rest of the papers, for all the stars, I will have to get via ILL or some other way.) In addition to reading these two papers, Ihave written summaries of them so that they can easily be referenced when Ihave new stars to research. Also, I have picked up a (e-)copy of Cataclysmic Variable Stars by Brian Warner, which seems to be a fairly reputable text on the subject. I'm mostly skimming it now, not paying too close attention to the derivations and math, just so I can get a handle on the context and terminology as well as why the data I'm looking at are interpreted the way they are. So, I've had a busy weekend, but it has been productive! Clear skies, Chase

Chase, I just read your post with great interest. I would very much like to read the papers you've referenced. I'm leading the new Kepler team here and I expect I'll need to how these assessments are made for binary systems. Can you post the references? I can get the docs through my school library. Thank you, Carol J (carolj12)

Certainly, Carol, and greetings!The original publications were written by Paula Szdoky, et al., who was part of the Sloan Digital Sky Survey. They all focus cataclysmic variables discovered during the SDSS, one paper per year.Szkody, P., et al., 2002. Cataclysmic variables from the Sloan Digital Sky Survey. I. The first results, Astron. J., 123, 430-442Szkody, P., et al., 2003. Cataclysmic variables from the Sloan Digital Sky Survey. II. The second year, Astron. J., 126, 1499-1514Szkody, P., et al., 2004. Cataclysmic variables from the Sloan Digital Sky Survey. III. The third year, Astron. J., 128, 1882-1893and so on; you'll find the rest. They all have the same title, just different years published.

Whoops, Ishould amend that the TiO spectrum in SDSS 0137 is from the secondary, which appears to be a M dwarf, not the white dwarf primary --C

This is just to note that the EV Aqr project is now taken by someone who sent a private note to us.

Hi, James. May I make a couple of off-topic administrative suggestions? First, I think you have a cool project going here. How about forming an official Citizen Sky team to organize it? We can assignArne to help mentor it for now. Just click here to fill out the application and Rebecca will set it up for you. If you want to invite others you can, but it can remain a team of one as well. Secondly, how about moving the rest of this thread to the Data Analysis forum? That way others can get into the discussion and we can keep this thread focused on discussion of project ideas.

Hi Aaron. I'm sorry Ididn't think of either of those things first! I hope Iwasn't crowding anyone out. I'll be happy to move the thread to a more suitable location. I'll also go ahead and fill out the team application. Iwouldn't mind others joining if they would like to help out. Thanks for the good suggestions! Chase