Apr 23, 2010 Author: Ralph Tuellmann (rtuellmann@cfa.harvard.edu) Meaning of some cryptic FITS columns in the binary extension of merged_pns4e-6_vd1.9.srclist: --------------------------------------------------------------------------------------------- CATALOG_NAME -> source ID (= RSD_SRC_ID, where RSD stands for Revised Source catalog, version. D) MODEL -> Best-fit XSPEC model (see below) RA -> Source's Right Ascension (J2000) Dec -> Source's Declination (J2000) FP5_8 -> absorption-corrected flux (the 'F') in the zero point five ('P5') to eight ('_8') keV energy band FP5_8U -> upper uncertainty value of the flux (90% confidence) FP5_8L -> lower uncertainty value of the flux (90% confidence). E.g. F2_8L would be the lower uncertainty of the flux in the (2 - 8)keV band. NET_CNTS -> background-subtracted source counts. This is actually a vector column with 13 subentries. Each of the 13 columns stands for one particular energy band. The coding is as follows: 1 2 3 4 5 6 7 8 9 10 11 12 13 eband_lo=[0.5, 0.5, 2.0, 0.5, 1.0, 2.0, 4.0, 0.35, 0.35, 0.35, 1.10, 2.60, 0.35] eband_hi=[8.0, 2.0, 8.0, 1.0, 2.0, 4.0, 8.0, 1.00, 8.00, 1.10, 2.60, 8.00, 2.00] PROB_NO_SOURCE -> 'pns' represents the Poisson probability that all of the counts within the source extraction region are actually from the background, i.e., source candidates with low probabilities are most likely real sources and vice versa. The catalog was filtered with pns<=4e-6. Mind: pns and many other column names are vector columns, too. The coding is the same as for NET_CTNS. FLUX2 -> If you want to use the sources' fluxes, use FLUX2, rather than FLUX1 values. See page 31, section 5.10.4 of the AE user manual (version June 9, 2008) for details. NH0, and -> For the automated spectral fitting in AE the following 2 models were assumed: NH0_MIN/MAX tbabs(tbvarabs*pow)) and tbabs(tbvarabs*vapec)). tbabs models the Galactic column density and is frozen at NH0=0.06x10^22cm^-2. tbvarabs is the N_H in M33 and is allowed to vary during the fit. In contrast to tbabs, which uses Galactic abundances, tbvarabs allows for variable abundances which are set to 0.5. All _MIN/_MAX parameters are the hard limits of the allowed paramterspace which are used by XSPEC. The two models generally produce different red. Chi squares. The model with the lower Chi square was considered to fit the data best, provided the kT of the vapec model was reasonable (<8keV). Only the MODEL parameter in 'merged_pns4e-6_vd1.9.srclist.gz' contains the best-fit model, so ignore this column in the individual .collated files should you have received some. RSD_SRC_ID -> This is the RSD source ID and identical with CATALOG_NAME RSD_SRC_NUMBER -> Position of the source in RSD FLC_SRC_NUMBER -> Position of the RSD source in FLC (Plucinsky et al. 2008), i.e. RSD source 013240.86+303550.3 is the 12th entry in RSD and the 9th in FLC. XMM_SRC_NUMBER -> RSD cross-correlated with the Pietsch et al. (2004), and Misanovic et al. (2006) XMM-Newton source catalog GRIMM_SRC_NUMBER -> RSD cross-correlated with the Grimm et al. 2005 catalog (ApJS 161, 271) Extension_flag -> Provides an estimate whether the source is possibly extended (=2), extended (=1), or not extended (=0). ERR_DATA -> Positional uncertainties (in arcsec) based on the individual position estimates provided by AE. See Tuellmann et al. (2011) for details. eta and xi -> Eta is the 5 sigma variability index and is sensitive to long-term variability. Sources with eta >= 5.0 are very likely to show long-term variability. Xi is the KS probability of the source being constant within a single observation (short-term variability). Sources with KS probabilities of xi <= 5.7e-07 are very likely to show short-term variability. flux_ratio -> Variability factor defined as flux_max/flux_min in the 0.35-8KeV energy band surfb_halpha -> Halpha surface brightness measured in 2" radius regions using the LGGS data from Massey et al. (2006). aka -> 'Also known as' = aliases for the sources. Data taken from FLC (Plucinsky et al. 2008), the SNR catalog (Long et al. 2010), from the XMM-Newton survey of M33 (Pietsch et al. 2004 & Misanovich et al. 2006), and from the list of transient sources (Williams et al. 2008). Based on optical follow-up spectroscopy available at the time when RSD was released (Feb 2010) and on multi-wavelength data (Spitzer, 2MASS, HST, LGGS, MegaCam, Swift, Galex, CXO, and 21cm radio data. Sources are classified as: FS = foreground stars stellar = objects whose spectra look star-like (e.g., stellar associations) and are likely to be located in M33 SNR = SNR-like spectra (to be distinguished from HII regions by significantly stronger [SII] emission lines XRBs = known XRBs and XRB candidates, from HP01, PMH04, MPH06 QSO/AGN = sources with broad and redshifted emission lines Galaxy = redshifted emission lines, but no broadened emission line components as typically seen in QSOs/AGN; source is obviously extended (from inspection of LGGS/MCam/HST data) non-stellar = everything which is not classified as stellar, but looked extended in the LGGS/MCam/HST data and did not match any of the other classes