Browsing by Author "Mora, Marcelo D."

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    A STARBURST IN THE CORE OF A GALAXY CLUSTER : THE DWARF IRREGULAR NGC 1427A IN FORNAX
    (2015) Mora, Marcelo D.; Chaname, Julio; Puzia, Thomas H.
  • No Thumbnail Available
    Item
    Clues on Arp 142: The spiral–elliptical merger
    (OUP, 2019) Mora, Marcelo D.; Torres-Flores, S.; Firpo, V.; Hernandez-Jimenez, J. A.; Urrutia-Viscarra, F.; Mendes de Oliveir, C.
    Nearby merging pairs are unique laboratories in which one can study the gravitational effects on the individual interacting components. In this manuscript, we report the characterization of selected H II regions along the peculiar galaxy NGC 2936, member of the galaxy pair Arp 142, an E+S interaction, known as ‘The Penguin’. Using Gemini South spectroscopy, we have derived a high enhancement of the global star formation rate (SFR) = 35.9 M ⊙ yr −1 probably stimulated by the interaction. Star-forming regions on this galaxy display oxygen abundances that are consistent with solar metallicities. The current data set does not allow us to conclude any clear scenario for NGC 2936. Diagnostic diagrams suggest that the central region of NGC 2936 is ionized by active galactic nucleus (AGN) activity and the eastern tidal plume in NGC 2936 is experiencing a burst of star formation, which may be triggered by the gas compression due to the interaction event with its elliptical companion galaxy: NGC 2937. The ionization mechanism of these sources is consistent with shock models of low velocities of 200–300 km s  −1 . The isophotal analysis shows tidal features on NGC 2937: at inner radii non-concentric (or off-centring) isophotes, and at large radii, a faint excess of the surface brightness profile with respect to de Vaucouleurs law. By comparing the radial velocity profiles and morphological characteristics of Arp 142 with a library of numerical simulations, we conclude that the current stage of the system would be about 50 ± 25 Myr after the first pericentre passage.
  • Thumbnail Image
    Item
    On collision course: The nature of the binary star cluster NGC2006/SL 538
    (2019) Mora, Marcelo D.; Puzia, Thomas H.; Chaname, Julio
  • No Thumbnail Available
    Item
    Signatures of tidal disruption in the Milky Way globular cluster NGC 6981 (M72)
    (2021) Piatti, Andres E.; Mestre, Martin F.; Carballo-Bello, Julio A.; Carpintero, Daniel D.; Navarrete, Camila; Mora, Marcelo D.; Cenzano, Carolina
    We study the outer regions of the Milky Way globular cluster NGC 6981 based on publicly available BV photometry and new Dark Energy Camera (DECam) observations, both of which reach nearly 4 mag below the cluster main sequence (MS) turnoff. While the BV data sets reveal the present of extra-tidal features around the cluster, the much larger field of view of the DECam observations allowed us to identify some other tidal features, which extend from the cluster toward the opposite direction to the Milky Way center. Such structural features of clusters arise from stellar density maps built using MS stars, following a cleaning of the cluster color-magnitude diagram to remove the contamination of field stars. We also performed N-body simulations in order to help us to understand the spatial distribution of the extra-tidal debris. The outcomes reveal the presence of long trailing and leading tails that are mostly parallel to the direction of the cluster velocity vector. We find that the cluster loses most of its mass by tidal disruption during its perigalactic passages, each of which lasted nearly 20 Myr. Hence, a decrease in the density of escaping stars near the cluster is expected from our N-body simulations, which, in turn, means that stronger extra-tidal features could be found by exploring much larger areas around NGC 6891.