LKHA101CXO ivo://nasa.heasarc/lkha101cxo NASA/GSFC HEASARC Wolk et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This table contains some of the results from a multi-wavelength study of a partially embedded region of star formation centered on the Herbig Be star LkH-alpha 101. Using two 40 ks Chandra observations, The authors have detected 213 X-ray sources in the ~ 17' x 17' ACIS-I field. They combine the X-ray data with Two Micron All Sky Survey (2MASS) near-IR observations and Spitzer Space Telescope (SST) IRAC and MIPS 24-micron observations to obtain a complete picture of the cluster. A total of 158 of the X-ray sources have infrared counterparts. Of these, the authors find nine protostars, 48 Class II objects, five transition objects, and 72 Class III objects. From the Spitzer data, they identify an additional 10 protostars, 53 Class II objects, and four transition disk candidates which are not detected by Chandra. (These objects are not included in this HEASARC table which contains the multi-wavelength data for only the 213 detected X-ray sources). The authors obtained optical spectra of a sample of both X-ray-detected and non-X-ray-detected objects. Combining the X-ray, Spitzer, and spectral data, they obtain independent estimates of cluster distance and the total cluster size - excluding protostars. The authors obtain consistent distance estimates of 510 (+100,-40) pc and a total cluster size of 255 (+50,-25) stars. They find the Class II:III ratio is about 5:7 with some evidence that the Class III sources are spatially more dispersed. The cluster appears very young with three sites of active star formation and a median age of about 1 Myr. The field was observed by Chandra on 2005 March 6 starting at 17:16 UT for 40.2 ks of total time and 39.6 ks of the so-called good time (Chandra ObsID 5429). It was observed again on 2005 March 8 starting at 17:43 UT for essentially the same duration (Chandra ObsID 5428). The ACIS was used in the nominal imaging array (chips I0-I3) which provides a field of view of approximately 17' x 17'. The aimpoint was at RA, Dec = 04:30:14.4, +35:16:22.2 (J2000.0) with a roll angle of 281 degrees. In addition, the S2 and S3 chips were active; however, the analysis of these data is not presented here. For purposes of point-source detection, the data from the two observations were merged into a single event list following established CIAO procedures to create a merged event list. To identify point sources, photons with energies below 300 eV and above 8.0 keV were filtered out from this merged event list. This excluded energies which generally lack a stellar contribution. By filtering the data as described, contributions from hard, non-stellar sources such as X-ray binaries and active galactic nuclei (AGNs) are attenuated, as is noise. A monochromatic exposure map was generated in the standard way using an energy of 1.49 keV which is a reasonable match to the expected peak energy of the stellar sources and the Chandra mirror transmission. The CIAO tool WavDetect was then run on a series of flux-corrected images binned by 1, 2, and 4 pixels. The output source lists were combined and this resulted in the detection of 231 sources. The authors defined false detections as any sources with < 4 net counts or any sources more than 5' off-axis with < 7 net counts. By this definition, 18 of the 231 detections were rejected as false detections. A post facto check confirmed that none of these (spurious) sources had an infrared counterpart. This table was created by the HEASARC in July 2010 based on the versions of Tables 1, 2, 3, 7 and 9 from the paper which were obtained from the electronic ApJ web site. This is a service provided by NASA HEASARC . 2010ApJ...715..671W https://heasarc.gsfc.nasa.gov/W3Browse/all/lkha101cxo.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=lkha101cxo& GET text/xml 180 99999 true 67.47320833 35.11113889 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=lkha101cxo GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_lkha101cxo&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 Infrared X-ray public lkha101cxo LkH-alpha 101 Star Formation Region Chandra X-Ray Point Source C name Catalog Source Designation (LkHa101CXO JHHMMSS.ss+DDMMSS.s) 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 off_axis Offset from Axis (arcmin) arcmin instr.offset double nullable counts Net Counts ct phot;em.X-ray double nullable jmag 2MASS J Band Magnitude mag phot.mag;em.IR.J double nullable jmag_error Uncertainty in 2MASS J Band Magnitude mag stat.error;phot.mag;em.IR.J double nullable irac_3p6_um_mag Spitzer IRAC 3.6-Micron Band Magnitude mag phot.mag;em.IR.3-4um double nullable irac_3p6_um_mag_error Uncertainty in Spitzer IRAC 3.6-Micron Band Magnitude mag stat.error;phot.mag;em.IR.3-4um double nullable cxo_spitzer_offset X-Ray/Spitzer Positional Offset (arcsec) arcsec pos.angDistance;em.X-ray;em.IR double nullable spectral_counts Net Spectral Counts ct phot;em.X-ray double nullable kmag 2MASS K Band Magnitude mag phot.mag;em.IR.K double nullable obs_flux Absorbed Flux (erg/s/cm^2) erg/s/cm^2 phot.flux;em.X-ray double nullable nh_error 1-Sigma Uncertainty in NH cm^-2 stat.error;phys.columnDensity double nullable hmag_error Uncertainty in 2MASS H Band Magnitude mag stat.error;phot.mag;em.IR.H double nullable reduced_chi_squared Reduced Chi^2 of the Fit stat.fit.chi2 double nullable nh Hydrogen Column Density cm^-2 phys.columnDensity double nullable cxo_2mass_offset X-Ray/2MASS Positional Offset (arcsec) arcsec pos.angDistance;em.X-ray;em.IR double nullable lii Galactic Longitude degree pos.galactic.lon double nullable gl_index Gregory & Loredo 1992 Index meta.code;src.var short nullable limit_kt Limit Flag for Effective Temperature meta.code;phys.temperature;stat.fit.param char nullable raw_counts Raw Counts ct phot;em.X-ray short nullable twomass_flags Flags Indicates Quality of 2MASS Photometry meta.code.qual;phot char nullable flare_rates Flare Rate(s) in Units of 1e4/R * dr/dt s^-1 meta.code;src.var char nullable irac_8p0_um_mag_error Uncertainty in Spitzer IRAC 8.0-Micron Band Magnitude mag stat.error;phot.mag;em.IR.4-8um double nullable irac_5p8_um_mag_error Uncertainty in Spitzer IRAC 5.8-Micron Band Magnitude mag stat.error;phot.mag;em.IR.4-8um double nullable mips_24_um_mag Spitzer 24-Micron Band Magnitude mag phot.mag;em.IR.15-30um double nullable num_bayesian_blocks Number of Bayesian Blocks stat.param;src.var short nullable kt_error 1-Sigma Uncertainty in Effective Temperature keV stat.error;phys.temperature;stat.fit.param double nullable class Browse Object Classification src.class short nullable hmag 2MASS H Band Magnitude mag phot.mag;em.IR.H double nullable irac_5p8_um_mag Spitzer IRAC 5.8-Micron Band Magnitude mag phot.mag;em.IR.4-8um double nullable kt Effective Temperature (keV) keV phys.temperature;stat.fit.param double nullable gl_probability Gregory & Loredo 1992 Probability stat.probability;src.var double nullable source_number Sequential Identification Number for Each Source in Catalog meta.id;src short nullable irac_4p5_um_mag_error Uncertainty in Spitzer IRAC 4.5-Micron Band Magnitude mag stat.error;phot.mag;em.IR.4-8um double nullable spectral_model Model Used in Fit meta.code;spect;meta.modelled char nullable irac_4p5_um_mag Spitzer IRAC 4.5-Micron Band Magnitude mag phot.mag;em.IR.4-8um double nullable broad_type Broad Classification src.class char nullable kmag_extinction The K Band Extinction mag double nullable irac_8p0_um_mag Spitzer IRAC 8.0-Micron Band Magnitude mag phot.mag;em.IR.4-8um double nullable source_note Note Concerning Source meta.note;src char nullable mips_24_um_mag_error Uncertainty in Spitzer 24-Micron Band Magnitude mag stat.error;phot.mag;em.IR.15-30um double nullable flux Unabsorbed Flux (erg/s/cm^2) erg/s/cm^2 phot.flux;em.X-ray double nullable bii Galactic Latitude degree pos.galactic.lat double nullable kmag_error Uncertainty in 2MASS K Band Magnitude mag stat.error;phot.mag;em.IR.K 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