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J/A+A/605/A54         ESO 435-02/ESO 435-016 ATCA HI images         (Kim+, 2017)

HI properties and star formation history of a fly-by pair of blue compact dwarf galaxies. Kim J., Chung A., Wong O.I., Lee B., Sung E.-C., Staveley-Smith L. <Astron. Astrophys. 605, A54 (2017)> =2017A&A...605A..54K (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, peculiar ; Radio sources ; H I data Keywords: galaxies: individual: ESO 435-020 - galaxies: individual: ESO 435-016 - galaxies: interactions - galaxies: ISM - galaxies: kinematics and dynamics - galaxies: starburst Abstract: A fly-by interaction has been suggested to be one of the major explanations for enhanced star formation in blue compact dwarf (BCD) galaxies, yet no direct evidence for this scenario has been found to date. In the HI Parkes all-sky survey (HIPASS), ESO 435-IG 020 and ESO 435-G 016, a BCD pair were found in a common, extended gas envelope of atomic hydrogen, providing an ideal case to test the hypothesis that the starburst in BCDs can be indeed triggered by a fly-by interaction. Using high-resolution data from the Australia Telescope Compact Array (ATCA), we investigated HI properties and the spectral energy distribution (SED) of the BCD pair to study their interaction and star formation histories. The high-resolution HI data of both BCDs reveal a number of peculiarities, which are suggestive of tidal perturbation. Meanwhile, 40% of the HIPASS flux is not accounted for in the ATCA observations with no HI gas bridge found between the two BCDs. Intriguingly, in the residual of the HIPASS and the ATCA data, ∼10% of the missing flux appears to be located between the two BCDs. While the SED-based age of the most dominant young stellar population is old enough to have originated from the interaction with any neighbors (including the other of the two BCDs), the most recent star formation activity traced by strong Hα emission in ESO 435-IG 020 and the shear motion of gas in ESO 435-G 016, suggest a more recent or current tidal interaction. Based on these and the residual emission between the HIPASS and the ATCA data, we propose an interaction between the two BCDs as the origin of their recently enhanced star formation activity. The shear motion on the gas disk, potentially with re-accretion of the stripped gas, could be responsible for the active star formation in this BCD pair. Description: The HI observations were conducted on March 27 and 28 2002 with the ATCA in EW367 array configuration (project ID of C1024). The ATCA primary beam is 33.1-arcmin at 1416MHz, which is comparable to the angular distance between the pair of galaxies of ∼30.3-arcmin. With a single pointing, the sensitivity at the locations of the galaxies hence drops by a factor of ∼1.8, and therefore we had two extra pointings centered on each galaxy in order to keep the desired sensitivity toward the pair. The observing frequency was centered on 1416MHz with a total bandwidth of 8MHz, which is configured into 512 channels, yielding a channel width of 3.3km/s. Objects: ---------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------- 09 59 21.23 -28 08 00.0 ESO 435-020 = LEDA 28863 09 58 46.22 -28 37 18.9 ESO 435-016 = LEDA 28822 ---------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 123 1 Information on fits datacube datacube.fits 2880 392 ESO 435-016/ESO 435-020 ATCA HI data cube
Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000) 10- 18 F9.5 deg DEdeg Declination of center (J2000) 20- 21 I2 --- Nx Number of pixels along X-axis 23- 25 I3 --- Ny Number of pixels along Y-axis 27- 28 I2 --- Nz Number of slices 30- 39 A10 "date" Obs.Date Observation date 41- 47 F7.3 km/s bVel Lower value of velocity interval 49- 54 F6.1 km/s BVel Upper value of velocity interval 56- 62 F7.5 km/s dVel Velocity resolution 64- 67 I4 Kibyte size Size of FITS file 69- 81 A13 --- FileName Name of FITS file 83-123 A41 --- Title Title of the FITS file
Acknowledgements: Aeree Chung, achung(at)
(End) Patricia Vannier [CDS] 14-Sep-2017
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

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