Formation of a Tidal Dwarf Galaxy in the Interacting System Arp 245 (NGC 2992/93)

By P. Duc, E. Brinks, Volker Springel, Barbara Pichardo, P. Weilbacher, I. Mirabel. 2000

171 citations recorded by the source corpus.

Among the various phenomena observed in interacting galaxies is the ejection due to tidal forces of stellar and gaseous material into the intergalactic medium and its subsequent rearranging which can lead to the formation of self-gravitating tidal dwarf galaxies (TDGs). We investigate this process with a detailed multiwavelength study of the interacting system Arp 245 and a numerical model of the collision computed with a Tree-SPH code. Our observations consist of optical/near-infrared broadband imaging, Hα imaging, optical spectroscopy, H I VLA cartography and CO line mapping. The system, composed of the two spiral galaxies NGC 2992 and NGC 2993, is observed at an early stage of the interaction, about 100 Myr after perigalacticon, though at a time when tidal tails have already developed. The VLA observations disclose a third partner to the interaction: an edge-on, flat galaxy, FGC 0938, which looks strikingly undisturbed and might just be falling toward the NGC 2992/93 system. Our H I map shows prominent counterparts to the optical tails. Whereas the stellar and gaseous components of the plume that originates from NGC 2992 match, the stellar and H I tails emanating from NGC 2993 have a different morphology. In particular, the H I forms a ring, a feature that has been successfully reproduced by our numerical simulations. The H I emission in the system as a whole peaks at the tip of the NGC 2992 tail where a gas reservoir of about 109 M⊙, about 60% of the H I toward NGC 2992, coincides with a star-forming optical condensation, A245N. The latter tidal object exhibits properties ranging between those of dwarf irregular galaxies (structural parameters, gas content, star formation rate) and those of spiral disks (metallicity, star formation efficiency, stellar population). Although it is likely, based on our analysis of the H I and model data cube, that A245N might become an independent dwarf galaxy, the dynamical evidence is still open to debate. Prompted by the questions raised for this particular object, we discuss some issues related to the definition and identification of TDGs and highlight some specific conditions which seem required to form them. Finally, we outline what is needed in terms of future numerical simulations in order to further our understanding of these objects.

Subfields: Astronomy and Astrophysics, Electrical and Electronic Engineering, Instrumentation

View Paper: https://www.semanticscholar.org/paper/0908f9b0e21e5797f45b205d7607039ac77237f1

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Electrical and Electronic Engineering

In Instrumentation

Citations in the corpus

HYDRODYNAMICS OF HIGH-REDSHIFT GALAXY COLLISIONS: FROM GAS-RICH DISKS TO DISPERSION-DOMINATED MERGERS AND COMPACT SPHEROIDS (2010, background): “The outermost clumps, those formed at more than 50 kpc from the center in model C1, could become dwarf galaxies formed during the merger (tidal dwarf galaxies (TDGs) Duc et al. 2000).”
The very local Hubble flow (2002, background): “…LF for members of groups with respect to the field LF may be described as a result of two processes: a) formation of objects of high luminosity (“cannibals”) due to merging of galaxies in groups, b) creation of new ”tidal” dwarfs, say, via fragmentation of tidal bridges and tails (Duc et al. 2000).”
Multiple minor mergers: formation of elliptical galaxies and constraints for the growth of spiral disks (2007, background): “The orbital parameters of a merging pair of galaxies have been described e.g. by Duc et al. (2000).”
High-Resolution H I Mapping of NGC 4038/39 (“The Antennae”) and Its Tidal Dwarf Galaxy Candidates (2001, background): “It is curious that a similar superthin galaxy was also serendipitously discovered by Duc et al. (2000) in their HI mapping of the interacting system NGC 2992/3, another interacting pair with a candidate Tidal Dwarf within a gas-rich tidal tail.”
Star Formation from Galaxies to Globules (2001, background): “Galaxies with a few long and symmetric arms (Kuno et al. 1995) or tidal arms (Rodrigues et al. 1999; Duc et al. 2000; Braine et al. 2001) have comparable collapse sites, but they are located inside the arms, strung out like beads with the same Jeans length spacing.”