Author Topic: Wednesday, 20th July, 2011: Yet Another Zooite Discovery (Another First)  (Read 2960 times)

JeanTate

  • OotD posters
  • Hero Member
  • *****
  • Posts: 2976
    • View Profile


Not the most catching of eye candy, is it? The object in the center is SDSS J003615.26+385131.6, which has gri magnitudes of 23.23, 23.28, and 22.24, respectively; extremely faint, whatever it is.

Zooming out a bit:



Hmm, there seem to be rather a lot of stars, but otherwise nothing to suggest anything worthy of being an OOTD.

Quote
The Palomar Transient Factory (Law et al. 2009, Rau et al. 2009) discovered a nova candidate in M31, PTF11fzx, on UT 2011 June 18.50 at RA(J2000)=00:36:15.3, Dec(J2000)=+38:51:31.7. PTF11fzx was R=19.0mag when discovered and fainter than a limiting magnitude of R=20.5 on June 12. The above magnitudes are calibrated to the USNO-B1 catalogue.

Spectra of PTF11fzx were obtained with the Double Beam Spectrograph on the Palomar 200-inch Hale telescope on June 24 and with the Low Resolution Image Spectrometer on the Keck-I telescope on July 2. The P200 spectrum exhibits a blue continuum without prominent Balmer series. The Keck spectrum shows strong Balmer lines (FWHM Halpha ~800 km/s) which are blueshifted by v~-300 km/s, consistent with M31. The existence of Fe II emission lines are indicative of the Fe II spectroscopic class of classical novae (Williams et al. 1994).

This nova is located about 170 arcmin away from the center of M31. Comparing to the Pietsch 2010 compilation, PTF11fzx is the most distant spectroscopically classified classical nova in M31.

That's the contents of ATel #3498, entitled "PTF discovery and classification of a classical nova in the outskirts of M31".

A classical nova is a white dwarf star that is accreting matter (mostly hydrogen) from its close binary companion, usually a red giant. The hydrogen builds up on the white dwarf's surface until it gets dense (and hot) enough to go off like an H-bomb; when it does that, the star brightens a lot, well over a thousand-fold and maybe over a million-fold. A classical nova is one which has been observed to have just one outburst; if there's been more than one, it's called a recurrent nova (both are types of cataclysmic variable - AAVSO, the American Association of Variable Star Observers, which is actually global (despite its name) - has a great page explaining the different types of variables, here).

M31, the Andromeda Nebula, has already featured as an OOTD; here's a DR8 Navigate image that shows the nova's location on its outskirts (you can just see part of the obvious spiral arms in the diagonal purple band at the top):



Now novae in M31 are a dime a dozen; so many, in fact, that the IAU's Central Bureau for Astronomical Telegrams doesn't even send out a notice when one is discovered (well, usually):

Quote
As stated elsewhere at this CBAT website, novae in M31 are relatively common (unlike their counterparts in the Magellanic Clouds or the Milky Way, which have only a few observed novae each year). There are roughly a couple dozen novae to be discovered (brighter than about mag 20) in M31 each year [cf., e.g., Capaccioli et al. 1989, A.J. 97, 1622; Hatano et al. 1997, Ap.J. 487, L45; Aguirre 2000, Sky Tel. 99(6), 80]. For this reason, we generally do not announce M31 novae on IAUCs unless they are brighter than about mag 15 or there is spectroscopic confirmation.

So, why make this one an OOTD?

Well, because it's the first M31 nova discovered by zooites!  ;D



Zooite robert gagliano posted this just two days' ago: SN Zoo finds Nova in Andromeda Galaxy.

Congratulations to zooites aethervox, ahiotis, bentemming, bickaroo, buddyjesus, chrostek, ElisabethB, fergie, GeorLewis, graham d, HelmutU, jwirthig, kaktus9, kiske1, kpax, lpspieler, nilium, robert gagliano, smj, voyager1682002, and WR!!  :)  :D  ;D

Lightbulb500

  • OotD posters
  • Hero Member
  • *****
  • Posts: 2354
    • View Profile
Yet more celebrations for the SN hunters ;D Excellent news ;D

Alice

  • Global Moderator
  • Hero Member
  • ****
  • Posts: 31782
    • View Profile
Whoopee - congratulations supernova addicts and thank you for another great write-up, Jean!

JeanTate

  • OotD posters
  • Hero Member
  • *****
  • Posts: 2976
    • View Profile
Re: Wednesday, 20th July, 2011: Yet Another Zooite Discovery (Another First)
« Reply #3 on: September 07, 2011, 09:57:33 am »
And the PTF (Palomar Transient Factory) has a link to us, right on their main page (under Recent News)!  :)  8)

JeanTate

  • OotD posters
  • Hero Member
  • *****
  • Posts: 2976
    • View Profile
Re: Wednesday, 20th July, 2011: Yet Another Zooite Discovery (Another First)
« Reply #4 on: October 26, 2011, 11:37:43 pm »
Pan-STARRS may routinely, and automatically, out-do zooites ... in respect of finding novae in M31!  :P  :o

From "PAndromeda - first results from the high-cadence monitoring of M31 with Pan-STARRS 1" (arXiv:1109.6320):

Quote from: C.H. Lee et al.
The Pan-STARRS 1 (PS1) survey of M31 (PAndromeda) is designed to identify gravitational microlensing events, caused by bulge and disk stars (self-lensing) and by compact matter in the halos of M31 and the Milky Way (halo lensing, or lensing by MACHOs). With the 7 deg2 FOV of PS1, the entire disk of M31 can be imaged with one single pointing. Our aim is to monitor M31 with this wide FOV with daily sampling (20 mins/day). In the 2010 season we acquired in total 91 nights towards M31, with 90 nights in the rP1 and 66 nights in the iP1. The total integration time in rP1 and iP1 are 70740s and 36180s, respectively. As a preliminary analysis, we study a 40'\times40' sub-field in the central region of M31, a 20'\times20' sub-field in the disk of M31 and a 20'\times20' sub-field for the investigation of astrometric precision. We demonstrate that the PSF is good enough to detect microlensing events. We present light curves for 6 candidate microlensing events. This is a competitive rate compared to previous M31 microlensing surveys. We finally also present one example light curve for Cepheids, novae and eclipsing binaries in these sub-fields.

Deep within the preprint: "During the time span of the first observing season of PAndromeda we find a few nova candidates in the central 40’×40’ sub-field. An example light curve is shown in Fig. 13."