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J/ApJ/641/763       UBVI photometry for Arp 220 star clusters    (Wilson+, 2006)

Two populations of young massive star clusters in Arp 220. Wilson C.D., Harris W.E., Longden R., Scoville N.Z. <Astrophys. J., 641, 763-772 (2006)> =2006ApJ...641..763W
ADC_Keywords: Clusters, globular ; Photometry, UBVRI Keywords: galaxies: starburst - galaxies: star clusters - galaxies: individual (Arp 220) - stars: formation Abstract: We present new optical observations of young massive star clusters in Arp 220, the nearest ultraluminous infrared galaxy, taken in UBVI with the Hubble Space Telescope ACS HRC camera. We find a total of 206 probable clusters whose spatial distribution is centrally concentrated toward the nucleus of Arp 220. We use model star cluster tracks to determine ages, luminosities, and masses for 14 clusters with complete UBVI indices or previously published near-infrared data. We estimate rough masses for 24 additional clusters with I<24mag from BVI indices alone. Description: Our new observations of Arp 220 were obtained with the Advanced Camera for Surveys (ACS) on 2002 August 11 through its High Resolution Channel (HRC), which has a field of view of 26"x29" and a scale of 0.027"/pix. The total integration time was 5460s in F330W(U), 1240s in F435W(B), 1200s in F555W(V), and 2640s in F814W (I). Objects: ------------------------------------------- RA (2000) DE Designation(s) ------------------------------------------- 15 34 57.21 +23 30 09.5 Arp 220 = IC 1127 ------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 75 206 ACS HRC photometry for Arp 220 star clusters table3.dat 81 14 Masses and ages for clusters in Arp 220
See also: J/A+A/372/L41 : NGC 2068/2071 protoclusters (Motte+, 2001) J/AJ/114/2381 : UBVI photometry of NGC 7252 (Miller+, 1997) J/AJ/109/960 : Young star clusters in The Antennae (Whitmore+ 1995) J/AJ/124/1418 : Radio-optical identification of star clusters (Whitmore+ 2002) J/ApJ/561/727 : BVI photometry in the Antennae galaxies (Zhang+, 2001) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 3 I3 --- [WHL2006] Cluster identification number ([WHL2006] in Simbad) 5- 10 F6.1 pix Xpix The X pixel coordinate 12- 17 F6.1 pix Ypix The Y pixel coordinate 19- 27 F9.6 h RAhour Hour of Right Ascension (J2000) 29- 36 F8.5 deg DEdeg Degree of Declination (J2000) 38- 43 F6.3 mag Imag The I band magnitude 45- 49 F5.3 mag e_Imag The 1σ error in Imag 51- 56 F6.3 mag V-I ? The (V-I) color index 58- 62 F5.3 mag e_V-I ? The 1σ error in V-I 64- 69 F6.3 mag B-V ? The (B-V) color index 71- 75 F5.3 mag e_B-V ? The 1σ error in B-V
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 2 I2 --- [WHL2006] Identification number ([WHL2006] in Simbad) 4- 9 F6.3 mag Vmag The V band magnitude 11- 15 F5.3 mag e_Vmag Error on Vmag 17- 21 F5.3 mag B-V ? The B-V color index 23- 27 F5.3 mag e_B-V ? Error on B-V 29- 34 F6.3 mag U-B ? The U-B color index 36- 40 F5.3 mag e_U-B ? Error on U-B 42 A1 --- l_V-H [<] Upper limit flag on V-H 43- 46 F4.2 mag V-H ? The V-H color index (1) 48- 51 F4.2 mag e_V-H ? Error on V-H (1) 53- 55 I3 Myr Age ? Cluster age (lower limit) 56 A1 --- --- [-] 59 I1 Myr Age2 ? Cluster age (upper limit) 60- 62 A3 --- n_Age2 Note on Age2 (2) 64- 67 F4.2 mag E(B-V) Reddening 69- 73 E5.3 solMass Mass1 The cluster mass or upper limit if interval 74 A1 --- --- [-] 75- 79 E5.3 solMass Mass2 ? Lower limit of mass if interval 81 I1 --- [SED98] ? Identification from Scoville et al. (1998ApJ...492L.107S)
Note (1): NICMOS 1.6µm photometry from Scoville et al. (1998ApJ...492L.107S; clusters [SED98] 1, 2 and 4) and Scoville et al. (2000AJ....119..991S; clusters 5, 11, 12 and 20). Note (2): Note on Age2, defined as follows: c = It is impossible to distinguish between these two young ages; the older age of 3Myr corresponds to the smaller mass. d = Since this cluster has only an upper limit to V-H, its reddening was estimated from the V-I color. e = Another possible solution is an unreddened 13Gyr cluster with a mass of 1x107M. A third possible solution is a 300Myr cluster with E(B-V)=0.56 and a mass of 3x106M. f = Another possible solution is an unreddened 13Gyr cluster with a mass of 7x106M.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 07-Apr-2008
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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