RHOOPHCXO ivo://nasa.heasarc/rhoophcxo NASA/GSFC HEASARC Imanishi et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source 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. This table was created by the HEASARC in February 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/PASJ/55/653">CDS Catalog J/PASJ/55/653</a> files table2.dat and table3.dat. This is a service provided by NASA HEASARC . 2003PASJ...55..653I https://heasarc.gsfc.nasa.gov/W3Browse/all/rhoophcxo.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=rhoophcxo& GET text/xml 180 99999 true 246.91616667 -24.72091667 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=rhoophcxo GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_rhoophcxo&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 Infrared X-ray public rhoophcxo Rho Ophiuchi SFR Chandra X-Ray Point Source Catalog name Catalog Source Designation meta.id;meta.main char nullable ra Right Ascension degree pos.eq.ra;meta.main double nullable dec Declination degree pos.eq.dec;meta.main double nullable counts Background-Subtracted ACIS-I Counts ct phot;em.X-ray double nullable te_plasma Time-Averaged Temperature (keV) keV double nullable lx Mean Absorption-Corrected X-Ray Luminosity in 0.5-9.0keV (erg/s) erg/s double nullable broad_class Broad Classification of the Source char nullable "__x_ra_dec" System unit vector column double nullable "__y_ra_dec" System unit vector column double nullable "__z_ra_dec" System unit vector column double nullable "__row" System index column char nullable te_plasma_upper 90% Confidence Upper Limit of Temperature (keV) keV double nullable bii Galactic Latitude degree pos.galactic.lat double nullable ctrpart_flag Flag Indicates Note Concerning Counterpart char nullable source_number Short Designation for Catalog Source meta.id char nullable log_em_lower_limit Limit Flag for Logarithm of Mean Emission Measure char nullable nh_upper 90% Confidence Upper Limit of Absorption Hydrogen Column Density (H atoms/cm^2) cm^-2 double nullable te_plasma_flag Flag Indicates Fixed Temperature char nullable nh_lower_limit Limit Flag for Absorption Hydrogen Column Density char nullable offset_flag Flag Indicates Type of Counterpart Used for Offset char nullable source_flag Notes on Catalog Entry char nullable lii Galactic Longitude degree pos.galactic.lon double nullable alt_name_4 Alternative Designation #4 meta.id char nullable log_em_mean Logarithm of Mean Emission Measure (in Units of cm^-3) log(cm^-3) double nullable asca_source_number X-Ray Source Detected by ASCA (Katama et al., 1997PASJ...49..461K) char nullable nh Absorption Hydrogen Column Density (H atoms/cm^2) H-atoms/cm^2 phys.columnDensity double nullable comments Comments Concerning Source char nullable te_plasma_lower_limit Limit Flag for 90% Confidence Lower Limit of Temperature char nullable counts_flag Flags: m=Marginal Detections, ++=Pile-Up Effect Not Corrected char nullable ikt2001_source_number Chandra Sources Already Listed in Imanishi et al., 2001ApJ...557..747I short nullable alt_name_8 Alternative Designation #8 meta.id char nullable flux Observed Flux in 0.5-9.0keV (erg/s/cm^2) erg/s/cm^2 phot.flux;em.X-ray double nullable hri_source_number X-Ray Source Detected by ROSAT/HRI (Grosso et al., 2000, Cat. J/A+A/359/113) char nullable hri_source_flag Flag Indicates ROSAT/HRI Source from Grosso (2001A&A...370L..22G) char nullable pspc_source_number X-Ray Source Detected by ROSAT/PSPC (Casanova et al., 1995ApJ...439..752C) char nullable broad_class_flag Flag Indicates Broad Classification Determined from NIR Spectroscopy char nullable radio_names Radio Source Designations, Separated by Commas char nullable asca_source_flag Flag Indicates ASCA Source from Tsuboi et al., 2000ApJ...532.1089T char nullable reduced_chi_squared Reduced Chi^2 of the Spectral Fit double nullable te_plasma_limit Limit Flag for Time-Averaged Temperature char nullable alt_name_3 Alternative Designation #3 meta.id char nullable alt_name_7 Alternative Designation #7 meta.id char nullable alt_name_6 Alternative Designation #6 meta.id char nullable off_set Offset Between the Chandra Source and the Nearest 2MASS Source (Cat. II/246) arcsec double nullable te_plasma_lower 90% Confidence Lower Limit of Temperature (keV) keV double nullable alt_name_2 Alternative Designation #2 meta.id char nullable nh_lower 90% Confidence Lower Limit of Absorption Hydrogen Column Density (H atoms/cm^2) cm^-2 double nullable log_em_lower 90% Confidence Lower Limit of Logarithm of Mean Emission Measure cm^-3 double nullable log_em_upper 90% Confidence Upper Limit of Logarithm of Mean Emission Measure cm^-3 double nullable alt_name_1 Alternative Designation #1 meta.id char nullable alt_name_5 Alternative Designation #5 meta.id char nullable entry_number Number Differentiates Multiple Entries of the Same Source short nullable dof Number of Degrees of Freedom of the Spectral Fit short nullable