NGC 6845 Revisited: Stellar Kinematics on the Early Type Member Galaxies

We observed the compact group of galaxies NGC 6845 with GMOS-S imaging and long-slit spectroscopy. The group itself is comprised of two spiral galaxies and two S0 galaxies, and shows signs of gravitational interaction among them. While the spiral galaxies have been already well studied, the two S0 galaxies have received little attention. We investigate the morphology and stellar kinematics of the two S0 galaxies in detail in order to derive the value for their mass and subsequently incorporate them into the mass model for the group. It was found that the internal kinematics of the largest S0 (NGC 6845 C) is mostly regular, while the smallest S0 (NGC 6845 D) shows some hint of interaction, most likely with NGC 6845 C and NGC 6845 A. The new determination of the dynamical mass of the group implies that the group mass has to be 10 times the combined mass of the individual members according to their internal kinematics. The results point to an early stage of the group interaction and also to the possibility that it has still not reached virial equilibrium. From the galaxy evolution viewpoint, this group represents an example of the case of the transformation of Spirals into S0 galaxies in dense environments.Fil: Gimeno, German Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Gemini Observatory; Estados UnidosFil: Díaz, Carlos Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Gemini Observatory; Estados Unidos. Universidad Nacional de Córdoba; ArgentinaFil: Dottori, Horacio Alberto. Universidade Federal do Rio Grande do Sul; BrasilFil: Rodrigues, Irapuan. Universidade do Vale do Paraíba; BrasilFil: Mast, Damian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentin

GNIRS NIR Integral Field Spectroscopy of NGC 5128

Presentamos observaciones del núcleo activo de NGC 5128 obtenidas con la unidad de campo integral (IFU) disponible en el espectrógrafo GNIRS hasta 2007. Este es el AGN más cercano y está completamente oculto al rango óptico por una fuerte línea de polvo debido al canto. orientación del disco de la galaxia. Los espectros IFU de banda K (1,9 - 2,55 μm) descubrieron la emisión nuclear y permitieron una nueva determinación de la masa del agujero negro supermasivo, además de mapear el gas molecular con una resolución espacial de ≈ 7 pc. Este trabajo nos permite explorar el potencial científico de las capacidades de campo integral en GNIRS, considerando que Gemini está actualizando el instrumento con la adición de dos IFU que trabajan en el rango espectral de 0,9 a 5,4 μm, que estarán disponibles a finales de 2021. Una de las IFU operará bajo visibilidad natural, lo que permitirá un campo de 3,2'' × 4.We present observations of the active nucleus of NGC 5128 obtained with the former integral field unit (IFU) of the GNIRS spectrograph. This is the nearest AGN and is completely hidden to the optical range by a strong dust lane due to the edge-on orientation of the galaxy disk. The K-band (1.9 to 2.55 µm) IFU spectra uncovered the nuclear emission and allowed a new determination of the supermassive black hole mass, plus mapping of the molecular gas with a spatial resolution of ∼7 pc. This work allows us to explore the scientific potential of the integral field capabilities in GNIRS, considering that Gemini is upgrading the instrument with the addition of two IFUs working in the spectral range 0.9 to 5.4 µm, which will be available by the end of 2021. One of the IFUs will operate under natural seeing, allowing a field of 3.2”×4.8” sampled each 0.15” with R∼7200. The other unit will complement Gemini North adaptive optics system, sampling each 0.05” a field of 1.25”×1.8”, with a spectral resolution R∼18000, uncommon for this kind of NIR 3D spectroscopy facility.Fil: Diaz, Ruben Joaquin. Gemini Observatory; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Mast, Damian. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Gaspar, Gaia. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Gunthardt, Guillermo Ivan. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Dottori, Horacio Alberto. Universidade Federal do Rio Grande do Sul; BrasilFil: Aguero Paz, Maria. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Comisión Nacional de Investigación Científica y Tecnológica; ChileFil: Camperi, Javier Antonio. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Diaz, Carlos Gonzalo. Gemini Observatory; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; ArgentinaFil: Gimeno, German Nicolas. Gemini Observatory; ChileFil: D'Ambra, Ary. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentin

Size and Shape Constraints of (486958) Arrokoth from Stellar Occultations

International audienceWe present the results from four stellar occultations by (486958) Arrokoth, the flyby target of the New Horizons extended mission. Three of the four efforts led to positive detections of the body, and all constrained the presence of rings and other debris, finding none. Twenty-five mobile stations were deployed for 2017 June 3 and augmented by fixed telescopes. There were no positive detections from this effort. The event on 2017 July 10 was observed by the Stratospheric Observatory for Infrared Astronomy with one very short chord. Twenty-four deployed stations on 2017 July 17 resulted in five chords that clearly showed a complicated shape consistent with a contact binary with rough dimensions of 20 by 30 km for the overall outline. A visible albedo of 10% was derived from these data. Twenty-two systems were deployed for the fourth event on 2018 August 4 and resulted in two chords. The combination of the occultation data and the flyby results provides a significant refinement of the rotation period, now estimated to be 15.9380 ± 0.0005 hr. The occultation data also provided high-precision astrometric constraints on the position of the object that were crucial for supporting the navigation for the New Horizons flyby. This work demonstrates an effective method for obtaining detailed size and shape information and probing for rings and dust on distant Kuiper Belt objects as well as being an important source of positional data that can aid in spacecraft navigation that is particularly useful for small and distant bodies