Access to Astronomical Catalogues

← Click to display the menu
J/ApJ/466/254                    NIR Imaging of R136 in 30 Dor (Brandl+ 1996)

Adaptive optics near-infrared imaging of R136 in 30 Doradus: the stellar population of a nearby starburst. Brandl B., Sams B.J., Bertoldi F., Eckart A., Genzel R., Drapatz S., Hofmann R., Loewe M., Quirrenbach A. <Astrophys. J. 466, 254 (1996)> =1996ApJ...466..254B
ADC_Keywords: Stars, dwarfs ; Photometry, UBVRIJKLMNH Keywords: H II regions - infrared: stars - ISM: individual (30 Doradus) - Magellanic Clouds - stars: early type - techniques: image processing Abstract: We report 0.15" resolution near-infrared (NIR) imaging of R136, the central region of 30 Doradus in the Large Magellanic Cloud. Our 12.8"x12.8" images were recorded with the MPE camera SHARP II at the 3.6m ESO telescope, using the adaptive optics system COME ON+. The high spatial resolution and sensitivity (20th magnitude in K) of our observations allow our H- and K-band images to be compared and combined with recent Hubble Space Telescope (HST) WFPC2 data of R136. We fit theoretical models with variable foreground extinction to the observed magnitudes of ∼1000 stars (roughly half of which were detected in HST and NIR bands) and derive the stellar population in this starburst region. We find no red giants or supergiants; however, we detect ∼110 extremely red sources which are probably young, pre-main-sequence low- or intermediate-mass stars. We obtained narrow-band images to identify known and new Wolf-Rayet stars by their He II (2.189um) and BrGamma (2.166um) emission lines. The presence of W-R stars and absence of red supergiants narrow the cluster age to 3-5Myr, while the derived ratio of W-R to O stars of 0.05 in the central region favors an age of ∼3.5Myr, with a relatively short starburst duration. For the O stars, the core radius is found to be 0.1pc and appears to decrease with increasing stellar mass. The slope of the mass function is Gamma=-1.6 on average, but it steepens with increasing distance from the cluster center from Gamma=-1.3 in the inner 0.4pc to Gamma=-2.2 outside 0.8pc for stars more massive than 12 Msun. The radial variation of the mass function reveals strong mass segregation that is probably due to the cluster's dynamical evolution. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table3.dat 51 971 The 971 main sequence stars in our field of view (YSO candidates and WR stars were excluded)
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Star Star number from Hunter et al. (1995ApJ...488..179H) 8- 10 I3 pix Xpos X position on detector (512x512 grid) 13- 15 I3 pix Ypos Y position on detector (512x512 grid) 18- 23 F6.2 mag Umag *?=-99.99 U magnitude 25- 30 F6.2 mag Vmag *?=-99.99 V magnitude 32- 37 F6.2 mag Imag *?=-99.99 I magnitude 39- 44 F6.2 mag Hmag *?=-99.99 H magnitude 46- 51 F6.2 mag Kmag *?=-99.99 K magnitude
Note on Umag, Vmag, Imag: The U, V & I band magnitudes were converted from WFPC2 magnitudes according the the relations in Hunter et al. (1995ApJ...488..179H). Extinction was not taken into account. Note on Hmag, Kmag: The H & K magnitudes were derived from the authors' observations with adaptive optics. Extinction is not taken into account.
Origin: AAS CD-ROM series, Volume 7, 1996 Lee Brotzman [ADS] 22-Oct-96
(End) [CDS] 03-Feb-1997
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

catalogue service