UV Morphology and Star Formation in the Tidal Tails of NGC 4038/9

J.E. Hibbard (NRAO), L. Bianchi (JHU), D. Thilker (JHU), R. M. Rich (UCLA), D. Schiminovich (Columbia, Caltech), C.K. Xu (Caltech), S. Neff (Goddard), M. Seibert (Caltech), S. Lauger (Marseille), D. Burgarella (Marseille), T.A. Barlow (Caltech), Y-I. Byun (Yonsei), J. Donas (Marseille), K. Forster (Caltech), P.G. Friedman (Caltech), T.M. Heckman (JHU), P.N. Jelinsky (Berkeley), Y-W. Lee (Yonsei), B.F. Madore (OCIW), R.F. Malina (Marseille), D.C. Martin (Caltech), B. Milliard (Marseille), P. Morrissey (Caltech), O.H.W. Siegmund (Berkeley), T. Small (Caltech), A.S. Szalay (JHU), B.Y. Welsh (Berkeley), and T.K. Wyder (Caltech)
The Astrophysical Journal Letters, 619, L87 (2005) (pdf 317 kB) (ADS) (astro-ph/0411352)

We present GALEX FUV (1530 A) and NUV (2310) observations of the archetypal merging system NGC 4038/39, ``The Antennae". Both tails are relatively bright in the UV, especially in the vicinity of the Tidal Dwarf Galaxy candidates at the end of the southern tail. The UV light generally falls within the optically delineated tails, although the UV light is considerably more structured, with a remarkably similar morphology to the tidal HI. The UV colors suggest that there has been continuing star formation within the tidal tails, even outside the previously studied Tidal Dwarf region. Within the inner disk regions, there are interesting UV features which appear to be related to the extended soft X-ray loops and halo recently discovered by Chandra.

Image to left: false color FUV (blue), FUV+NUV (green), NUV (red) GALEX image of NGC 4038/39. Go here for more figures on NGC 4038/9

Paper and Figures:

PDF of ApJL file (317 kB)
Figure 1: eps.gz (0.5 kB); jpg
Figure 2: eps.gz (0.8 kB); jpg
Panel (a) of Fig1: N4038 FUV,NUV falsecolor (jpg; blue=FUV, yellow=FUV+NUV, red=NUV)
Panel (c) of Fig2: Color coded ages for brighter UV regions in tails (red, orange = age as old or older than tail formation timescale of 300Myr; green, yellow, blue = younger than dynamical age of tail)

Additional Figures:

eps.gz of two options for fig2a,b: top=full res FUV (B),FUV+NUV (G),NUV (R) w/HI contours; bottom=low-res FUV (B), full res FUV+NUV (G), low-res NUV (R) w/HI contours.
Q.gif contours of Sigma_gas/Sigma_crit (=1.5, 3, 4.5), on FUV-NUV and FUV
Plots of UV surface brightness vs. HI column density. Red: (FUV-NUV)>1; GREEN: 1>(FUV-NUV)>0; BLUE: (FUV-NUV)<0. crosses=disk; triangles=TDG; diamonds=Ntail; stars=Stail: Linear; Log.
color.gif FUV-NUV, FUV-B, NUV-B.
ann.gif Galex greys with objects identified in Saviane et al. 2004 plotted as follows: upper left=stellar associations; upper right: add bright blue stars (t<30 Myr); lower right: add bright red stars (t~80-100 Myr); lower left=add faint blue stars. Compare this with Fig 9 of Saviane et al. 2004
eps.gz of original 12-panel fig1 (1.1 MB)
Poster presented at 205th AAS, Jan 9-13 2005, San Diego (1MB)

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