Chamaeleon I North Cloud Chandra X-Ray Point Source Catalog CHAINTHCXO ivo://nasa.heasarc/chainthcxo NASA/GSFC HEASARC Feigelson, Lawson 2026-10-02 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This table contains the Chamaeleon (Cha) I North Cloud Chandra X-Ray point source catalog. Sensitive X-ray imaging surveys provide a new and effective tool to establish the census of pre-main-sequence (PMS) stars in nearby young stellar clusters. A deep Chandra X-Ray Observatory (CXO) observation of PMS stars in the Chamaeleon I North cloud achieved a limiting total-band X-ray luminosity of log L&lt;sub&gt;t&lt;/sub&gt; ~ 10&lt;sup&gt;27&lt;/sup&gt; ergs/s (0.5 - 8 keV band) in a 0.8 x 0.8 pc&lt;sup&gt;2&lt;/sup&gt; region. Of the 107 X-ray sources, 37 are associated with Galactic stars, of which 27 are previously recognized cloud members. These include 3 PMS brown dwarfs: the protostellar brown dwarf ISO 192 has a particularly high level of magnetic activity. Follow-up optical photometry and spectroscopy establish that 9-10 of the Chandra sources are probably magnetically active background stars. No new X-ray-discovered stars were confidently found despite the high sensitivity of the Chandra observation. From these findings, the authors argue that the sample of 27 PMS cloud members in the Chandra field is uncontaminated and complete down to K = 12 or a stellar mass of about 0.1 solar masses. A 16&#39;x 16&#39; region of the Cha I North cloud was observed with the imaging array of the Advanced CCD Imaging Spectrometer (ACIS-I) detector on board the Chandra X-Ray Observatory. The observation took place on 2001 July 2.25-3.04 UT with the detector aimpoint set at 11 10 00.0, -76 35 00 (J2000.0 RA and Declination). The effective exposure was 66.3 ksec. The authors also obtained VI-band CCD images of most of the ACIS field with the 1m telescope and CCD detector at the South African Astronomical Observatory (SAAO) during 2002 February. This table was created by the HEASARC in February 2007 based on &lt;a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/614/267"&gt;CDS catalog J/ApJ/614/267&lt;/a&gt; files table1.dat, table2.dat and table3.dat. This is a service provided by NASA HEASARC . 2004ApJ...614..267F https://heasarc.gsfc.nasa.gov/W3Browse/all/chainthcxo.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=chainthcxo& GET text/xml 180 99999 true 167.73291667 -76.75911111 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=chainthcxo GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_chainthcxo&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 Infrared Optical X-ray public chainthcxo Chamaeleon I North Cloud 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 Extracted Counts phot;em.X-ray short nullable alt_name Stellar Counterpart meta.id char nullable rmag USNO-B1.0 (Cat. <I/284>) R Magnitude mag phot.mag;em.opt.R double nullable log_lx Logarithm of the Absorption-Corrected X-Ray Luminosity (in erg/s) log(erg/s) double 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_2 Plasma Energy 2 (keV) double nullable kmag 2MASS K Magnitude mag double nullable spect_type Spectral Type src.spType char nullable te_plasma_1_flag Flag Indicates Uncertainty in Plasma Energy 1 char nullable stellar_mass_flag Flag Indicates Uncertainty in Mass of Source char nullable off_set Offset between Chandra and 2MASS Positions (arcsec) arcsec double nullable te_plasma_1_error Error in Plasma Energy 1 (keV) keV double nullable log_nh Logarithm of Hydrogen Column Density in cm^-2 log(H-atoms/cm^2) double nullable off_axis Off-Axis Angle (arcmin) arcmin instr.offset double nullable stellar_age_limit Limit Flag for Age char nullable kmag_limit Limit Flag on K Magnitude char nullable note_flag Flag Indicates Source Lies at Edge of ACIS Detector char nullable iso_14p3um_mag 14.3-micron Band Magnitude from the Infrared Space Observatory Survey mag double nullable jmag 2MASS J Magnitude mag double nullable log_l_bol_flag Flag Indicates Uncertainty in Bolometric Luminosity char nullable variability_flag Flag Indicates Variability Based on Probability of the Kolmogorov-Smirnov Test char nullable te_plasma_1 Plasma Energy 1 (keV) keV double nullable kmag_flag Flag Indicates Uncertainty in K Magnitude char nullable hmag_flag Flag Indicates Uncertainty in H Magnitude char nullable lii Galactic Longitude degree pos.galactic.lon double nullable stellar_mass Source Mass (in units of the Solar mass) Solar_Mass double nullable source_number Sequential Identification Number for Each Source in Catalog meta.id short nullable log_lx_sb Logarithm of X-Ray Luminosity in the Soft 0.5-2keV Band (in erg/s) log(erg/s) double nullable stellar_age Age of Source (millions of years) Myr short nullable gross_counts Gross Counts from Extraction Region short nullable bck_counts Background Counts Scaled to the Extraction Region short nullable imag i or I Magnitude mag phot.mag;em.opt.I double nullable log_lx_obs Logarithm of X-Ray Luminosity in the Total 0.5-8keV Band (in erg/s) log(erg/s) double nullable property_flags Flags Indicates Properties of Star from Carpenter et al. (2002) char nullable log_l_bol Logarithm of Bolometric Luminosity (in units of the Solar luminosity) log(Solar_Luminosity) double nullable hmag 2MASS H Magnitude mag double nullable class Browse Object Classification src.class short nullable jmag_flag Flag Indicates Uncertainty in J Magnitude char nullable log_nh_flag Flag Indicates Uncertainty in Hydrogen Column Density char nullable chxr_number Cross-Reference to Earlier ROSAT Sources (Feigelson et al., 1993ApJ...416..623F) short nullable bii Galactic Latitude degree pos.galactic.lat double nullable iso_6p7um_mag 6.7-micron Band Magnitude from the Infrared Space Observatory Survey mag double nullable broad_class Classification Type char nullable