Formation of a tidal dwarf galaxy in the interacting system ARP 245 (NGC 2992/93)

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 w...

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Detalles Bibliográficos
Publicado:	2000
Materias:	Galaxies: individual (Arp 245, NGC 2992, NGC 2993, FGC 0938) Galaxies: interactions Methods: numerical
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00046256_v120_n3_p1238_Duc http://hdl.handle.net/20.500.12110/paper_00046256_v120_n3_p1238_Duc
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_00046256_v120_n3_p1238_Duc
record_format	dspace
spelling	paper:paper_00046256_v120_n3_p1238_Duc2023-06-08T14:27:11Z Formation of a tidal dwarf galaxy in the interacting system ARP 245 (NGC 2992/93) Galaxies: individual (Arp 245, NGC 2992, NGC 2993, FGC 0938) Galaxies: interactions Methods: numerical 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. 2000 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00046256_v120_n3_p1238_Duc http://hdl.handle.net/20.500.12110/paper_00046256_v120_n3_p1238_Duc
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Galaxies: individual (Arp 245, NGC 2992, NGC 2993, FGC 0938) Galaxies: interactions Methods: numerical
spellingShingle	Galaxies: individual (Arp 245, NGC 2992, NGC 2993, FGC 0938) Galaxies: interactions Methods: numerical Formation of a tidal dwarf galaxy in the interacting system ARP 245 (NGC 2992/93)
topic_facet	Galaxies: individual (Arp 245, NGC 2992, NGC 2993, FGC 0938) Galaxies: interactions Methods: numerical
description	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.
title	Formation of a tidal dwarf galaxy in the interacting system ARP 245 (NGC 2992/93)
title_short	Formation of a tidal dwarf galaxy in the interacting system ARP 245 (NGC 2992/93)
title_full	Formation of a tidal dwarf galaxy in the interacting system ARP 245 (NGC 2992/93)
title_fullStr	Formation of a tidal dwarf galaxy in the interacting system ARP 245 (NGC 2992/93)
title_full_unstemmed	Formation of a tidal dwarf galaxy in the interacting system ARP 245 (NGC 2992/93)
title_sort	formation of a tidal dwarf galaxy in the interacting system arp 245 (ngc 2992/93)
publishDate	2000
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00046256_v120_n3_p1238_Duc http://hdl.handle.net/20.500.12110/paper_00046256_v120_n3_p1238_Duc
_version_	1768546234324221952

Formation of a tidal dwarf galaxy in the interacting system ARP 245 (NGC 2992/93)

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