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J/ApJS/181/444  X-emitting stars identified from the RASS/SDSS  (Agueros+, 2009)

X-ray-emitting stars identified from the ROSAT All-Sky Survey and the Sloan Digital Sky Survey. Agueros M.A., Anderson S.F., Covey K.R., Hawley S.L., Margon B., Newsom E.R., Posselt B., Silvestri N.M., Szkody P., Voges W. <Astrophys. J. Suppl. Ser., 181, 444-465 (2009)> =2009ApJS..181..444A
ADC_Keywords: Cross identifications ; Photometry, SDSS ; Surveys ; X-ray sources Stars, late-type Keywords: surveys - X-rays: stars Abstract: The ROSAT All-Sky Survey (RASS) was the first imaging X-ray survey of the entire sky. Combining the RASS Bright and Faint Source Catalogs (Cat. IX/10, 1RXS and IX/29) yields an average of about three X-ray sources per square degree. However, while X-ray source counterparts are known to range from distant quasars to nearby M dwarfs, the RASS data alone are often insufficient to determine the nature of an X-ray source. As a result, large-scale follow-up programs are required to construct samples of known X-ray emitters. We use optical data produced by the Sloan Digital Sky Survey (SDSS) to identify 709 stellar X-ray emitters cataloged in the RASS and falling within the SDSS Data Release 1 footprint. Most of these are bright stars with coronal X-ray emission unsuitable for SDSS spectroscopy, which is designed for fainter objects (g>15[mag]). Instead, we use SDSS photometry, correlations with the Two Micron All Sky Survey and other catalogs, and spectroscopy from the Apache Point Observatory 3.5m telescope to identify these stellar X-ray counterparts. Our sample of 707 X-ray-emitting F, G, K, and M stars is one of the largest X-ray-selected samples of such stars. We identify 17 new X-ray-emitting DA (hydrogen) WDs, of which three are newly identified WDs. We report on follow-up observations of three candidate cool X-ray-emitting WDs (one DA and two DB (helium) WDs); we have not confirmed X-ray emission from these WDs. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 63 12 The CVs and WDs among the RASS/SIMBAD matches table3.dat 134 52 RASS sources with multiple candidate counterparts table4.dat 556 709 Full RASS/SDSS catalog table5.dat 94 27 New X-ray-emitting SDSS DA WDs table6.dat 94 8 X-ray-emitting SDSS non-DA WDs table7.dat 74 20 RASS/SIMBAD class II, III, IV, and A stars table8.dat 101 41 SIMBAD stars with Apache Point Obs. (APO) spectra
See also: III/210 : Spectroscopically Identified White Dwarfs (McCook+, 1999) IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999) IX/32 : ROSAT Bright Survey (Fischer+, 1998-2000) IX/29 : ROSAT All-Sky Survey Faint Source Catalog (Voges+ 2000) J/ApJS/117/319 : Northern RASS X-ray sources catalog (Appenzeller+ 1998) J/A+AS/131/197 : F, G and K stars BVRI photometry (Metanomski+ 1998) J/A+A/406/535 : Hamburg/RASS Cat. of optical ident. V3.0 (Zickgraf+, 2003) J/ApJS/149/29 : ROSAT North Ecliptic Pole Survey (Gioia+, 2003) J/A+A/427/387 : QORG catalog of radio/X-ray sources (Flesch+, 2004) : SDSS Home page Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 15 A15 --- 1RXS 1RXS designation (HHMMSS.s+DDMMSS) 17- 21 F5.3 s-1 Cts ROSAT count rate 23- 27 F5.3 s-1 e_Cts Error on Counts 29- 39 A11 --- XID Counterpart name in Simbad (WD or V*) 41- 44 F4.1 arcsec Offset Offset between X-ray source and optical counterpart 46- 50 F5.2 mag Bmag ?=- Simbad B-band magnitude 52- 56 F5.2 mag Vmag ?=- Simbad V-band magnitude 58- 63 A6 --- Type Object type (1)
Note (1): "P" indicates that CV is a polar and "DN" that it is a dwarf nova.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 15 A15 --- 1RXS Name (HHMMSS.s+DDMMSS) 17- 21 F5.3 s-1 Cts ? ROSAT counts rate 23- 27 F5.3 s-1 e_Cts ? Error on Counts 29- 46 A18 --- SDSS Name ( 48- 51 F4.1 arcsec Offset Offset between X-ray source and SDSS counterpart 53- 57 F5.2 mag gmag SDSS g-band magnitude 59- 63 F5.2 mag e_gmag Error on gmag 65- 69 F5.2 mag Jmag ?=- 2MASS J-band magnitude 71- 74 F4.2 mag e_Jmag ? Error on Jmag 76- 80 F5.2 [-] FX/FJ Log ratio of RASS X-ray to 2MASS J band fluxes 81 A1 --- f_FX/FJ [b] FX/FV ratio (1) 83- 85 A3 --- SpA Spectral Type (from Apache Point Obs.) 87-113 A27 --- XID Simbad counterpart 116-120 F5.2 mag Vmag ? Simbad V-band magnitude 122-126 F5.2 [-] FX/FV ? Corresponding Simbad log(FX/FV) 128-129 A2 --- SpT Simbad spectral type 131-133 A3 --- ObT Simbad object type 134 A1 --- f_XID [a] Problem with position in Simbad (2)
Note (1): b = log(Fx/FV). There is no 2MASS detection of this QSO. Note (2): a = the given SIMBAD position is offset by 37", but this appears to be the SDSS star.
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 15 A15 --- 1RXS RASS Name (HHMMSS.s+DDMMSS +1RXS J) 17- 26 F10.6 deg RAdeg RASS Right Ascension in decimal degrees (J2000) 28- 37 F10.6 deg DEdeg RASS Declination in decimal degrees (J2000) 39- 40 I2 arcsec e_Pos RASS position uncertainty (1) 42 I1 --- f_1RXS Flag on RASS (2) 44- 50 F7.5 ct/s CRate RASS count rate 52- 58 F7.5 ct/s e_CRate Uncertainty in CRate 60- 63 I4 s Exp RASS exposure time 65- 69 F5.2 --- HR1 First hardness ratio (3) 71- 74 F4.2 --- e_HR1 Uncertainty in HR1 76- 80 F5.2 --- HR2 Second hardness ratio (3) 82- 85 F4.2 --- e_HR2 Uncertainty in HR2 87- 88 I2 arcsec Ext Source extent 90 I1 --- EL Extent likelihood (See Voges et al., 1999, Cat. IX/10) 92- 94 I3 --- DL Detection likelihood (See Voges et al., 1999, Cat. IX/10) 96-113 A18 --- SDSS SDSS identification ( 115-124 F10.6 deg RA2deg SDSS Right Ascension in decimal degrees (J2000) 126-135 F10.6 deg DE2deg SDSS Declination in decimal degrees (J2000) 137-141 F5.2 arcsec offS-R Offset from SDSS and RASS positions 143-148 F6.3 mag umag SDSS u band PSF magnitude 150-155 F6.3 mag e_umag Uncertainty in umag 157-162 F6.3 mag gmag SDSS g band PSF magnitude 164-169 F6.3 mag e_gmag Uncertainty in gmag 171-176 F6.3 mag rmag SDSS r band PSF magnitude 178-184 F7.3 mag e_rmag Uncertainty in rmag 186-191 F6.3 mag imag ?=0.0 SDSS i band PSF magnitude 193-198 F6.3 mag e_imag Uncertainty in imag 200-205 F6.3 mag zmag ?=0.0 SDSS z band PSF magnitude 207-212 F6.3 mag e_zmag Uncertainty in zmag 214-228 A15 --- f_SDSS Flags on SDSS (4) 230-245 A16 --- 2MASS 2MASS identification (HHMMSSss+DDMMSSs) 247-256 F10.6 deg RA3deg 2MASS Right Ascension in decimal degrees (J2000) 258-267 F10.6 deg DE3deg 2MASS Declination in decimal degrees (J2000) 269-272 F4.2 arcsec offS-2 Offset from SDSS and 2MASS positions 274-279 F6.3 mag Jmag 2MASS J band magnitude 281-285 F5.3 mag e_Jmag ? Uncertainty in Jmag 287-292 F6.3 mag Hmag 2MASS H band magnitude 294-298 F5.3 mag e_Hmag Uncertainty in Hmag 300-305 F6.3 mag Ksmag ? 2MASS KS band magnitude 307-311 F5.3 mag e_Ksmag ? Uncertainty in Ksmag 313-315 A3 --- q_2MASS Quality flags on 2MASS (5) 317-321 F5.2 [-] FX/FJ Log ratio of RASS X-ray to 2MASS J band fluxes 323-326 F4.2 mag KsMAG ? Synthetic absolute KS band magnitude 328-333 F6.2 mag e_KsMAG ? Uncertainty in KsMAG 335-340 F6.2 pc Dist ? Star distance (corresponding to KsMAG) 342-347 F6.2 pc e_Dist ? Uncertainty in Dist 349-356 E8.2 10-7W LX ? RASS X-ray luminosity in erg/s 358-365 E8.2 10-7W e_LX ? Uncertainty in LX 367-370 I4 yr Obs.Y ? Year of the APO observation (6) 372-374 A3 --- Obs.M Month of the APO observation (6) 376-377 I2 d Obs.D ? Day of the APO observation (6) 379-386 A8 --- Type Source spectral type 388-414 A27 --- Simbad Simbad identification 416-425 F10.6 deg RA4deg ? Simbad Right Ascension in decimal degrees (J2000) 427-436 F10.6 deg DE4deg ? Simbad Declination in decimal degrees (J2000) 438-442 F5.2 arcsec offS-Si ? Offset from SDSS and Simbad positions 444-448 F5.2 mag Bmag ? Simbad B band magnitude 450-454 F5.2 mag Vmag ? Simbad V band magnitude 456-460 F5.2 [-] FX/FV ? Log ratio of RASS X-ray to Simbad V band fluxes 462-467 A6 --- Class Simbad classification (7) 469-556 A88 --- Note Additional note(s) (8)
Note (1): This is the total positional error (1σ error) and includes a 6 arcsec systematic error. Note (2): Summary of RASS flags. When = 0, the following are NOT true: * nearby sources affecting SASS flux determination; * possible problem with position determination; * source extended beyond SASS extraction radius; * complex diffuse emission pattern (see Voges et al., 1999, Cat. IX/10). Note (3): The hardness ratios are defined by HR1=(B-A)/(B+A), where A = count-rate in PHA range 11-41(∼0.1-0.4keV) and B = count-rate in PHA range 52-201(∼0.5-2.0keV) and HR2=(D-C)/(D+C), where C = count-rate in PHA range 52-90(∼0.5-0.9keV) and D = count-rate in PHA range 91-201(∼0.9-2.0keV) (PHA = Pulse Height Amplitude; see Voges et al., 1999, Cat. IX/10). Note (4): SDSS flags written in hexadecimal, full description available at (or see the SDSS Photometric Catalog, Cat. II/294) Note (5): Three character flag, one per band [JHK], that provides a summary of the net quality of the photometry in each band, as derived from the Read Flag, measurement uncertainties ([jhk]cmsig), scan signal-to-noise ratios ([JHK]snr), frame-detection statistics, and profile-fit reduced chi-squared values: X = There is a detection at this location, but no valid brightness estimate can be extracted using any algorithm. The default magnitude is null. U = Upper limit on magnitude. Source is not detected in this band, or it is detected, but not resolved in a consistent fashion with other bands. E = This category includes detections where the goodness-of-fit quality of the profile-fit photometry was very poor, or detections where psf fit photometry did not converge and an aperture magnitude is reported, or detections where the number of frames was too small in relation to the number of frames in which a detection was geometrically possible. A = Detections in any brightness regime where valid measurements were made with [JHK]snr>10 AND [JHK]cmsig<0.10857. B = Detections in any brightness regime where valid measurements were made with [JHK]snr>7 AND [JHK]cmsig<0.15510. C = Detections in any brightness regime where valid measurements were made with [JHK]snr>5 AND [JHK]cmsig<0.21714. D = Detections in any brightness regime where valid measurements were made with no [JHK]snr OR [JHK]cmsig requirement. Note (6): For stars observed more than once, the data listed are that of the first APO observation. Note (7): Object types as follows: ** = double or multiple star system; *i* = star in double system; * = star; PM* = high proper-motion star; WU* = W UMa-type eclipsing binary; LM* = low-mass star (<1M); BY* = BY Dra-type variable; Al* = Algol-type binary; V* = variable star; X = X-ray source; bL* = beta Lyr-type eclipsing binary; SB* = spectroscopic binary; Rad = radio source; RR* = RR Lyrae star; *iC = star in a cluster; EB* = eclipsing binary. Note (8): Includes the spectral type derived from APO observations for stars with types listed in SIMBAD and/or the Flesch & Hardcastle (2004, Cat. J/A+A/427/387) or Parejko et al. (2008AJ....135...10P) classification for the source counterpart. RM = a random match between the Flesch & Hardcastle (2004, Cat. J/A+A/427/387) source catalogs is most likely in this case; SX = a stellar source; SX? = a probable stellar source; X = an unclassified X-ray source; G = a galaxy; R = a radio source; U = the source is an unclassifiable galaxy in the Parejko et al. catalog (2008AJ....135...10P); T = a transition object; HII = a star-forming galaxy; E = an emission galaxy; UE = the emission is unclassified; CC = close companion (≲5") star.
Byte-by-byte Description of file: table[56].dat
Bytes Format Units Label Explanations
1- 18 A18 --- SDSS SDSS designation ( 19 A1 --- f_SDSS [bc] Individual notes (1) 21- 26 I6 K Teff ?=- Effective temperature 28- 31 I4 K e_Teff ? Error on Teff 32 A1 --- u_Teff Uncertainty flag on Teff 34- 48 A15 --- 1RXS Name (HHMMSS.s+DDMMSS) 50- 53 F4.1 arcsec Offset Offset between SDSS and X-ray sources 55- 59 F5.3 s-1 Cts Counts 61- 65 F5.3 s-1 e_Cts Error on counts 67- 71 F5.2 [-] FX/FG Log ratio of RASS X-ray to SDSS g-band fluxes 72 A1 --- f_FX/FG [a] Flag on Log(FX/FG) (2) 74- 80 A7 --- Type Type (for Table 6) 82- 92 A11 --- XID McCook & Sion (1999, Cat. III/210) WD designation 94 A1 --- f_XID [u] uncertain identifications (3)
Note (1): Flag as follows: b = Post-DR4 WD. c = SDSS J0936 (in Table 5) is listed as a DQ WD by McCook & Sion (1999, Cat. III/210). However, the SDSS spectrum does not show the carbon absorption lines typical of DQs, and it seems that this is indeed a DA WD. Note (2): a = g photometry is flagged in SDSS (for Table 5 only). Note (3): u = tentative identifications requiring further observations, on the contrary, lack of "u" means highly secure RASS counterpart identifications (for Table 5 only).
Byte-by-byte Description of file: table7.dat
Bytes Format Units Label Explanations
1- 15 A15 --- 1RXS Name (HHMMSS.s+DDMMSS) 17- 21 F5.3 s-1 Cts Counts 23- 27 F5.3 s-1 e_Cts Error on counts 29- 46 A18 --- Name HD, BD, CCDM or V* designation 48- 52 F5.2 arcsec Offset Offset between X-ray source and optical counterpart 54- 58 F5.2 mag Vmag V-band magnitude 60- 64 F5.2 [-] FX/FV Log ratio of RASS X-ray to Simbad V band fluxes 66- 70 A5 --- SpType Spectral type 72- 74 A3 --- OType Object type (1)
Note (1): "**" or "*i*" indicates a double or multiple star system, "RR*" an RR Lyrae star, and "Al*" an Algol-type binary.
Byte-by-byte Description of file: table8.dat
Bytes Format Units Label Explanations
1- 15 A15 --- 1RXS Name (HHMMSS.S+DDMMSS) 17- 34 A18 --- SDSS Name ( 35 A1 --- f_SDSS [f] Possibly several counterparts (1) 37- 40 F4.1 arcsec off1 Offset between RASS & SDSS positions 42- 68 A27 --- XID Counterpart Simbad name 70- 72 A3 --- f_XID [abcdegh, ] Flag on Simbad name (2) 74- 76 F3.1 arcsec off2 Offset between SDSS & Simbad positions 78- 84 A7 --- SpT2 Published spectral type 86- 95 A10 "YYYY/MM/DD" ObsDate First APO observation date 97- 99 A3 --- SpA Apache Point Obs. Spectral type 101 A1 --- f_1RXS [c] Non-secure Fx/Fopt estimation (3)
Note (1): f = One of two possible counterparts to this source (see Table 3). This star was not included in the flux ratio calculations discussed in Section 4.1.1. Note (2): Flag as follows: a = X-ray source identified by Schwope et al. (2000AN....321....1S). b = X-ray source identified by Appenzeller et al. (1998, Cat. J/ApJS/117/319). c = X-ray source identified by Zickgraf et al. (2003, Cat. J/A+A/406/535). d = X-ray source identified by Metanomski et al. (1998, Cat. J/A+AS/131/197) e = X-ray source identified by Fischer et al. (1998, Cat. IX/32). g = X-ray source identified by Gioia et al. (2003, Cat. J/ApJS/149/29). h = APO target is not the same star. Note (3): Stars without "c" are those for which choosing the APO or the SIMBAD spectral class does not impact (FX/Fopt) calculations.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 22-Oct-2009
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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