J/ApJ/351/492 X-ray emission in the Ursa Major stream. (Schmitt+, 1990)
X-ray studies of coeval star samples. III. X-ray emission in the Ursa Major stream. Schmitt J.H.M.M., Micela G., Sciortino S., Vaiana G.S., Harnden F.R., Rosner R. <Astrophys. J. 351, 492 (1990)> =1990ApJ...351..492S
ADC_Keywords: Clusters, open ; Stars, emission ; X-ray sources Mission_Name: Einstein Keywords: clusters: open - stars: rotation - stars: X-rays Abstract: Results are reported from a comprehensive survey of X-ray emission from stars known or suspected to be members of the UMa cluster and/or stream. Of the 42 UMa member stars surveyed, 18 were detected as X-ray sources, and spectral analysis was performed for 10 stars with sufficient X-ray counts. Consideration is given to relations between X-ray luminosity, color, and kinematics of the sample stars, and the X-ray spectra of the UMa stars are discussed in the context of the general problem of stellar X-ray temperatures. Also confirmed is the lack of X-ray-emitting A dwarfs among UMa members; among stars of later spectral type there is a rather large dispersion in X-ray luminosity. This dispersion cannot readily be explained by contamination with field star interlopers and appears rather to be a property of the UMa X-ray luminosity distribution function. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file st_uma_1.dat 119 42 X-ray Emssion in the Ursa Major Stream: X-ray Results and Optical Properties st_uma_3.dat 72 10 X-ray Emission in the Ursa Major Stream: Temperature Fits
See also: J/ApJ/315/687 X-Ray emission from solar-type stars: F and G J/ApJ/348/253 Einstein Survey of Late-type Giant and Supergiant Stars J/ApJ/325/798 Einstein Survey of Hyades-cluster Region J/ApJ/348/557 Einstein Survey of the Pleiades Cluster Byte-by-byte Description of file: st_uma_1.dat
Bytes Format Units Label Explanations
2- 5 I4 --- HR HR (Bright Star Catalog) number (1) 7- 12 I6 --- HD HD (Henry Draper Catalog) number (1) 14- 16 A3 --- inst Instrument (2) 18- 22 I5 --- Seqno Sequence Number (2) 24 I1 --- f_CCR Flagged "1" if count rate is an upper limit (3) 26- 30 F5.1 ct/ks CCR Corrected Count Rate (3) 32- 35 F4.1 ct/ks e_CCR Error on count rate (3) 37 A1 --- method Detect method (4) 39- 43 F5.2 [10-7W] logLx Log of X-ray luminosity from 0.16-4.0 keV (5) 45 A1 --- note Notes on the source (6) 47- 48 I2 h RAh Right Ascension (B1950) (hour) 50- 51 I2 min RAm Right Ascension (B1950) (min) 53- 57 F5.2 s RAs Right Ascension (B1950) (sec) 59 A1 --- DE- Declination sign (B1950) 60- 61 I2 deg DEd Declination (B1950) (deg) 63- 64 I2 arcmin DEm Declination (B1950) (arcmin) 66- 69 F4.1 arcsec DEs Declination (B1950) (arcsec) 71- 75 F5.1 pc Dist Distance to star (7) 77- 81 F5.2 mag B-V B-V color index (7) 83- 93 A11 --- Sp Spectral type (7) 95- 99 F5.2 km/s U U velocity (8) 101-106 F6.2 km/s V V velocity (8) 108-113 F6.2 km/s W W velocity (8) 115-119 F5.2 km/s Rho Velocity (8)
Note (1): These columns give the HR (Bright Star Catalog) and HD (Henry Draper Catalog) numbers of the sample star. Note (2): These columns give the instrument used and the sequence number of the observation. Listed in the instrument column will be an "I" if the Imaging Proportional Counter (IPC) was used, an "H" if the High Resolution Imager (HRI) was used, or an "EXO" if the data is from EXOSAT. The Einstein sequence number is a two to five digit number which uniquely identifies the observation. The numbers were assigned sequentially at the time of proposal submission. In most cases we used IPC data, for a few stars the HRI was used, and in one case the EXOSAT Low Energy experiment was used. Note (3): The "f_CCR" column is marked with a "1" if the corrected count rate is an upper limit. The "CCR" column gives the corrected count rate (per 1000 seconds). For detections, the "f_CCR" column is marked with a "0", and the 1 sigma error is given in the "e_CCR" column. For upper limits, the value given is a 3 sigma upper limit, and the error is given as zero. Count rate is corrected for scattering, vignetting, and detector dead time. Note (4): This column marks what kind of detect algorithm was used to locate the source; an "M" indicates MDETECT, an "L" indicates LDETECT (see Harnden, et al. 1984). This pertains only to the IPC data. Sources detected with other detectors contain a "." in this column. Note (5): This column gives the log of the X-ray luminosity (in erg/s) in the 0.16-4.0 keV passband, computed with the distance given in the table stuma2.dat . When the count rate is an upper limit, the luminosity is also an upper limit. For the conversion from count rate to fluxes, we used the "standard" conversion of 2x10-11 erg/cm2/count. Note (6): This column contains notes on individual sources. The following notes are used: a: HR 1971: observed with Ribs and Edges COde (RECO; see text) 1008 b: HR 5328/29: not separated by IPC; observed with RECO 200 c: HR 5727/28: not separated by IPC d: HR 8207: observed with RECO 1006 e: HR 8410: observed with RECO 400 Note (7): In these columns, we give the adopted distance, the B-V color index, and the spectral type. Note (8): The space velocities, U, V, and W are given (in km/s) in the first three columns listed here. Note that we are using a coordinate system with the positive U-axis pointing toward the Galactic center. In the "Rho" column, we give the modulus of the velocity difference between the star and the cluster nucleus adopted from Eggen (1983AJ.....88..642E) to be U(nuc)= 13.9 km/s, V(nuc)= 1.5 km/s, and W(nuc)= -9.4 km/s.
Byte-by-byte Description of file: st_uma_3.dat
Bytes Format Units Label Explanations
2- 7 I6 --- HD HD (Henry Draper Catalog) number (1) 9- 13 I5 --- Seqno Sequence number (2) 15 I1 --- ntemps Number of temperature components in fit (3) 17- 20 F4.2 [K] logT1 log T for low-temperature component (4) 22- 25 F4.2 [K] e_logT1 Downward 68% confidence error (4) 27- 30 F4.2 [K] E_logT1 Upward 68% confidence error (4) 32- 35 F4.2 [K] logT2 log T for high-temperature component (4) 37- 40 F4.2 [K] e_logT2 Downward 68% confidence error (4) 42- 45 F4.2 [K] E_logT2 Upward 68% confidence error (4) 47- 50 F4.2 --- chi2 Reduced chi-square (5) 52- 55 F4.2 10+49/cm3/pc2 em1d2 Emission measure (6) 57- 60 F4.2 10+49/cm3/pc2 em2d2 Emission measure (6) 62- 66 F5.2 [10-7W] logLx1 log X-ray luminosity from 0.16-4.0 keV (7) 68- 72 F5.2 [10-7W] logLx2 log X-ray luminosity from 0.16-4.0 keV (7)
Note (1): The HD (Henry Draper Catalog) number of the sample star is given in this column. Note (2): This column gives the Einstein sequence number, a two to five digit number which uniquely identifies the observation. Sequence numbers were assigned sequentially at the time of proposal submission. Note (3): This column gives the number of temperature components which were used in the spectral analysis. Note (4): These columns give the best-fit single temperature for each component (logT1 and logT2), along with the one sigma (68% confidence) errors. For fits which had only one component, the second component entries will be zero. Note (5): This column gives the reduced chi-squared of the temperature fit. Note (6): These columns give the derived emission measure (in units of 1049 cm-3 pc-2) of the best-fit spectrum. For fits which had only one component, the entry for the second component will be zero. Note (7): These columns give the log of the inferred X-ray luminosity (with the distance as given in stuma1.dat) in ergs/s in the 0.16-4.0 keV passband. For fits which had only one component, the entry for the second component will be zero
History: Prepared from the tables available at the "ADS Catalogue Service" (CfA, Harvard-Smithsonian Center for Astrophysics, Cambrigde MA) References: Harnden, F.R., Jr., Fabricant, D.G., Harris, D.E., and Schwarz, J. 1984, Smithsonian Ap. Obs. Spec. Rept., No. 393.
(End) Patricio Ortiz [CDS] 07-Apr-1999
|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|