RHOOPHCXO - Rho Ophiuchi SFR Chandra X-Ray Point Source Catalog

Overview

This catalog of X-ray sources represents some of the results of a systematic study of X-ray flares from low-mass young stellar objects, using two deep exposure Chandra observations of the main region of the rho Ophiuchi star-forming cloud. From 195 X-ray sources, including class I-III pre-main sequence sources and some young brown dwarfs, a total of 71 X-ray flares were detected.

The Chandra X-ray Observatory (Weisskopf et al., 2002PASP..114....1W) observed the central region of rho Oph twice with a deep exposure of the ACIS-I array, consisting of four abutted X-ray CCDs. The first observation (here and after, obs. BF) covered the south-east 17.4' x 17.4' area, including cores B, C, E, and F, while the second observation (obs. A) covered the north-west area centered on core A (Loren et al., 1990ApJ...365..269L).

This table contains data and the results of spectral and timing analyses on the 195 sources detected in the two rho Oph fields, 9 of which were detected in both fields and are therefore listed twice (A-61=BF-2, A-64=BF-4, A-65=BF-5, A-69=BF-7, A-75=BF-11, A-77=BF-15, A-78=BF-16, A-79=BF-17, and A-81 = BF-19). Sources which flared have multiple entries, with one entry (typically, but not always) listing the properties of the quiescent emission, and additional entries for individual flares which were analyzed separately. For the very faint sources for which the temperatures obtained from X-ray spectral analyses were not constrained, there are typically two entries in this table per source, one of which gives the results of a spectral analysis in which the temperature was fixed at 1 keV (11.6 MK) and the other in which the temperature was instead fixed at 5 keV (58 MK). Thus, there are more entries (306) in this HEASARC table than the number (195) of detected rho Oph X-ray sources.

Catalog Bibcode

2003PASJ...55..653I

References

A systematic study of X-ray flares from low-mass young stellar objects in the
rho Ophiuchi star-forming region with Chandra.
    Imanishi K., Nakajima H., Tsujimoto M., Koyama K., Tsuboi Y.
   <Publ. Astron. Soc. Jap., 55, 653 (2003)>
   =2003PASJ...55..653I

Provenance

This table was created by the HEASARC in February 2007 based on CDS Catalog J/PASJ/55/653 files table2.dat and table3.dat.

Parameters

Source_Number
A unique designation for each catalog source, of the form 'field-(band) number' using a prefix identifying the particular field (A or BF) in which the source was detected, an optional letter (S or H) if the source was only detected in either the soft-band (0.5 - 2.0 keV) or the hard-band (2.0 - 9.0 keV), and a running number in order of increasing J2000.0 Right Ascension within each of these sub-categories, e.g., 'A-66', 'BF-H4', etc. Thus, the sources from the first observation are labeled A-NN (NN=1 to 84), A-HN (N=1-5) for the hard (2.0 - 9.0 keV) band, and A-SN (N=-1-5) for the soft (0.5 - 2.0 keV) band, whereas the sources from the second observation are labeled BF-NN (1-98), BF-HN (N=1-4) for the hard (2.0 - 9.0 keV) band, and BF-SN (N=1-8) for the soft (0.5 - 2.0 keV) band.

Name
The name for the catalogued X-ray source based on the '[INT2003]' prefix (for Imanishi, Nakajima and Tsujimoto, 2003) and the source number, as recommended by the CDS Dictionary of Nomenclature of Celestial Objects. As discussed elsewhere, since different spectral and/or temporal analyses could be made of individual sources, there can be multiple entries in this table for the same source.

Entry_Number
This HEASARC-created parameter differentiates multiple entries of the same X-ray source in this table. Sources which flared can have multiple entries corresponding to either flares and/or quiescent emission periods or, for very faint sources, to different assumptions about the characteristic plasma temperature.

Source_Flag
This parameter contains flags corresponding to the following source notes:

  a = The authors have determined spectral parameters with fixed temperatures of
      1 keV and 5 keV (see text of reference paper). For sources which only show
      the parameters for either kT = 1 or 5 keV, no good fits were obtained for
      the other temperature.
  b = They assume the same abundances as the ``F2'' phase in Imanishi et
      al. (2002ApJ...572..300I). The quiescent spectrum is not obtained
      because the decay phases of the two flares occupy all of the light curve.
  d = No spectral fit is done due to the limited statistics
  e = Abundances are free parameters (see sub-subsection 4.8.1 in
      Paper I, Imanishi et al., 2001ApJ...557..747I and Imanishi, 2003,
      PhD Thesis, Kyoto University)
  f = They made the flare spectra with a bit larger time scale in order to
      obtain as good statistics as possible. Errors of <EM> for A-29 in
      the quiescent are not determined because of the limited statistics
  g = The spectra show possible edge absorption of neutral Ca or warm Ar.
      The non-thermal model also well reproduces the spectra (Hamaguchi,
      Imanishi, 2002, PASJ, submitted)
  h = They assume the same temperature because of the limited statistics.
  i = These show non-thermal spectra (Imanishi, 2003, PhD Thesis,
      Kyoto University)
  k = Imanishi et al. (2002ApJ...572..300I) proposed
      two-temperature model with an unusual abundance pattern
  l = Foreground star. The distance is 60pc (Festin, 1998A&A...336..883F)
  m = The best-fit value of <kT> is not determined (larger than 10keV),
      hence we assume 10keV temperature for the estimation of the other
      parameters.
  n = NH and reduced-chi² are estimated by the simultaneous fittings
      with the identical sources in obs. A.

Counts
The background-subtracted ACIS-I counts of the X-ray source. The quoted X-ray counts can be in the 0.5 - 2.0 keV, 2.0 - 9.0 keV, or 0.5 - 9.0 keV energy ranges (the soft bands, hard bands, and total bands, respectively). For most sources, the counts are in the total band; for sources detected only in the soft band or hard band (these sources are indicated by the presence of the 'S' or 'H' prefixes in their names), the counts are for the ranges in which they were detected.

Counts_Flag
This parameter contains flags corresponding to the following notes concerning the source counts reliability:

  m   = denotes sources with marginal detections (the confidence level <99.9%,
        see Section 3.1 of the reference). Although the confidence levels of
        A-48 and A-H2 are significant enough, the authors regard them as
        marginal sources because of the larger source size (A-48) and severe
        contamination from A-2 (A-H2).
  ++  = The pile-up effect is not corrected

RA
The Right Ascension of the X-ray source in the selected equinox. This was given in J2000.0 coordinates to a precision of 0.01 seconds of time in the reference paper.

Dec
The Declination of the X-ray source in the selected equinox. This was given in J2000.0 coordinates to a precision of 0.1 arcseconds in the reference paper.

LII
The Galactic Longitude of the X-ray source.

BII
The Galactic Latitude of the X-ray source.

Te_Plasma_Limit
This parameter is set to '>' if the corresponding parameter value for the time-averaged temperature is a lower limit.

Te_Plasma
The time-averaged temperature of the emitting plasma as derived from or assumed in the spectral analysis, in keV.

Te_Plasma_Lower_Limit
This parameter is set to '>' if the corresponding parameter value for the 90% confidence lower limit to the time-averaged temperature has no corresponding upper limit, i.e., the maximum temperature is unconstrained.

Te_Plasma_Lower
The 90% confidence lower limit to the time-averaged temperature, in keV.

Te_Plasma_Upper
The 90% confidence upper limit to the time-averaged temperature, in keV.

Te_Plasma_Flag
This parameter is a flag which is set to 'f' to indicate that the quoted temperature was fixed at that value in the spectral analysis, rather than having been derived from the spectral analysis.

Log_EM_Mean
The logarithm of the mean Emission Measure EM of the emitting plasma, as derived from spectral analysis, in units of cm^-3.

Log_EM_Lower_Limit
This parameter is set to '<' if the corresponding parameter value for the 90% confidence lower limit to the time-averaged Emission Measure value is unconstrained.

Log_EM_Lower
The 90% confidence lower limit for the logarithm of EM, in cm^-3.

Log_EM_Upper
The 90% confidence upper limit for the logarithm of EM, in cm^-3.

NH
The X-ray absorption, in terms of the equivalent hydrogen column density. N_H, as derived from spectral analysis, in units of H atoms/cm².

NH_Lower_Limit
This parameter is set to '<' or '>' if the corresponding parameter value for the absorption hydrogen column density is only constrained on the upper or lower limit side. The HEASARC notes that the '>' values quoted for the source number A-37 are inconsistent with the best-fit values N_H for this source, and likely should have been entered as '<' values.

NH_Lower
The 90% confidence lower limit for the absorption column density, in H atoms/cm².

NH_Upper
The 90% confidence upper limit for the absorption column density, in H atoms/cm².

Flux
The observed flux of the X-ray source, in the 0.5 - 9.0 keV energy range, in erg/s/cm².

Lx
The mean absorption-corrected luminosity of the X-ray source, in the 0.5 - 9.0 keV energy range, in erg/s.

Reduced_Chi_Squared
The reduced chi-squared Chi_red² of the spectral fit.

DoF
The number of degrees of freedom for the spectral fit.

Comments
Some brief comments concerning the source properties or identification, or on the nature of the emission, e.g., quiescent or flare.

Offset
The angular offset between the Chandra X-ray source and the nearest 2MASS (CDS Cat. II/246) source, in arcseconds, except as noted by a non-blank value of the offset_flag parameter which indicates the offset from either a nearby radio source or an IR source from another catalog.

Offset_Flag
This parameter flags that the offset was measured between the Chandra source and a non-2MASS counterpart, as follows:

  (R) = for sources having a radio counterpart only, the offset between
        the Chandra and radio sources (Andre et al., 1987AJ.....93.1182A)
        are shown.
        (1992ApJ...395..516G).

Radio_Names
The name(s) of the proposed radio source counterparts to the X-ray source, separated by commas if more than one, using the following codes:

  R = Andre et al. (1987AJ.....93.1182A)} (ROC NN)
  S = Stine et al. (1988AJ.....96.1394S) (SFAM NN)
  L = Leous et al. (1991ApJ...379..683L) (LFAM NN)
  Lp denotes possible radio sources in LFAM.

PSPC_Source_Number
The counterpart X-ray source number detected by ROSAT/PSPC and listed in Casanova et al., 1995ApJ...439..752C.

HRI_Source_Number
The counterpart X-ray source number detected by ROSAT/HRI and listed in Grosso et al., 2000, CDS Cat. J/A+A/359/113, unless the value of hri_source_flag is '+' in which case the HRI source comes from Grosso (2001A&A...370L..22G).

HRI_Source_Flag
This parameter is set to '+' to flag that the ROSAT/HRI source comes from Grosso (2001A&A...370L..22G).

ASCA_Source_Number
The counterpart X-ray source number detected by ASCA and listed in Katama et al. (1997PASJ...49..461K), unless the value of asca_source_flag is '+' in which case the ASCA source comes from Tsuboi et al. (2000ApJ...532.1089T).

ASCA_Source_Flag
This parameter is set to '+' to flag that the ASCA source comes from Tsuboi et al. (2000ApJ...532.1089T).

IKT2001_Source_Number
The Chandra source number for the X-ray source listed in Imanishi et al. (2001ApJ...557..747I=IKT).

Alt_Name_1
The first alternative designation for the source as used in the literature, using the following abbreviations for their references (note that (i) for sources having NIR counterparts only in the 2MASS catalog, the authors alternatively show the 2MASS source names, and (ii) the HEASARC has listed only up to 8 of the alternative names given in Table 3 of the reference paper):

        SR: Struve, Rudkjobing, 1949ApJ...109...92S
      DoAr: Dolidze, Arakelyan, 1959AZh....36..444D
      ROXs: Bouvier, Appenzeller, 1992A&AS...92..481B
         S: Grasdalen et al., 1973ApJ...184L..53G
       YLW: Young et al., 1986ApJ...304L..45Y
        GY: Greene, Young, 1992ApJ...395..516G
        WL: Wilking, Lada, 1983ApJ...274..698W
      VSSG: Vrba et al., 1975ApJ...197...77V
       GSS: Grasdalen et al., 1973ApJ...184L..53G
     Elias: Elias, 1978ApJ...224..453E
     BBRCG: Barsony et al., 1989ApJ...346L..93B
      CRBR: Comeron et al., 1993ApJ...416..185C
       SKS: Strom et al., 1995, Cat. <J/ApJ/438/813>
       IRS: Wilking et al., 1989ApJ...340..823W
       ISO: Bontemps et al., 2001, Cat. <J/A+A/372/173>

Alt_Name_2
The second alternative designation for the source as used in the literature, using the abbreviations for their references as described above (note that the HEASARC has listed only up to 8 of the alternative names given in Table 3 of the reference paper).

Alt_Name_3
The third alternative designation for the source as used in the literature, using the abbreviations for their references as described above (note that the HEASARC has listed only up to 8 of the alternative names given in Table 3 of the reference paper).

Alt_Name_4
The fourth alternative designation for the source as used in the literature, using the abbreviations for their references as described above (note that the HEASARC has listed only up to 8 of the alternative names given in Table 3 of the reference paper).

Alt_Name_5
The fifth alternative designation for the source as used in the literature, using the abbreviations for their references as described above (note that the HEASARC has listed only up to 8 of the alternative names given in Table 3 of the reference paper).

Alt_Name_6
The sixth alternative designation for the source as used in the literature, using the abbreviations for their references as described above (note that the HEASARC has listed only up to 8 of the alternative names given in Table 3 of the reference paper).

Alt_Name_7
The seventh alternative designation for the source as used in the literature, using the abbreviations for their references as described above (note that the HEASARC has listed only up to 8 of the alternative names given in Table 3 of the reference paper).

Alt_Name_8
The eighth alternative designation for the source as used in the literature, using the abbreviations for their references as described above (note that the HEASARC has listed only up to 8 of the alternative names given in Table 3 of the reference paper).

Ctrpart_Flag
This parameter flags a note concerning the counterpart:

  + = The position of GY5 (Greene, Young, 1992ApJ...395..516G) is
      slightly shifted (~2.3") from the 2MASS source.
  S = A candidate of HH object (Gomez et al., 1998AJ....115.2018G).

Broad_Class
A fairly broad classification of the source, primarily based on the pre-main-sequence I/II/III infrared classification scheme. Unclassified NIR sources are indicated by "?", and sources with no NIR counterpart are called "unidentified sources", and have a blank field. For BD/BDc objects, the available IR classification in Bontemps et al. (2001, Cat. <J/A+A/372/173>) is shown in parentheses. Other possible values and their meanings are as follows:

  I    = class I YSO (infall envelope and accretion disk)
  II   = class II YSO (accretion disk)
  III  = class III YSO (remnant or absent accretion disk)
  IIIc = class III candidate (table 5 in Bontemps et al., 2001, CDS Cat.
         <J/A+A/372/173>)
  BD   = brown dwarf
  BDc  = brown dwarf candidate (Imanishi et al., 2001ApJ...563..361I)
  F    = foreground star (Festin, 1998A&A...336..883F).

Broad_Class_Flag
This parameter is set to 'a' to flag that the broad classification is determined from NIR spectroscopy and that Wilking et al. (1999AJ....117..469W) derived for these M dwarfs masses which are higher than the hydrogen burning limit.

Contact Person

Questions regarding the RHOOPHCXO database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:33:45 EDT