RevMexAA: Abstracts of Accepted Papers for Volume 48 Number 2

March 22, 2012

2012: March

March 2012

Chemical abundance of late-type spiral galaxies at the SDSS

A. M. Hidalgo-Gámez, A. Moranchel-Basurto, and A. F. González-Fajardo

Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, México, D. F., Mexico

Received: 2012 February 8
Accepted: 2012 March 22

Abstract: Oxygen abundances have been determined for a total of 15 late-type spiral galaxies. The intensities of the emission lines were determined from the spectra retrieved from the SDSS data-base. Only three galaxies have abundances previously reported in the literature. For four of them the forbidden oxygen line was detected in the spectra but the Te determined for three of them is larger than 20,000 K. The chemical abundances for the other galaxies were determined with the semi-empirical methods. The values indicate that, in general, the oxygen abundance of dS galaxies is smaller than for Sm ones.

Speckle Interferometry at the Observatorio Astronómico Nacional. IV

V. G. Orlov, V. V. Voitsekhovich, and C. A. Guerrero

Instituto de Astronomía, Universidad Nacional Autónoma de México, México, D. F., Mexico

Received: 2012 February 10
Accepted: 2012 March 12

Abstract: We present speckle interferometric measurements of binary stars performed during September and October of 2009 with the 2.1 m telescope of the Observatorio Astronómico Nacional at SPM (Mexico). We report here the results of 200 measurements of 196 pairs with a primary limiting magnitude of V=12.3. The measured angular separations range from 0”.115 to 5”.26. Ninety seven pairs have separations less than 1”. The mean error in separation is 0”.03 and 1.5 in position angle. The usual 180 ambiguity was corrected for a majority of position angles by comparison with observations performed by other observers.

The Filamentary Multi-polar Planetary Nebula NGC 5189

L. Sabin,1 R. Vázquez,1 J. A. López,1 Ma. T. García-Díaz,1 and G. Ramos-Larios2

1Instituto de Astronomía, Universidad Nacional Autónoma de México, Ensenada, B. C., Mexico
2Instituto de Astronomía y Meteorología, Departamento de Física, CUCEI, Universidad de Guadalajara, Jalisco, Mexico

Received: 2011 December 29
Accepted: 2012 March 5

Abstract: We present a set of optical and infrared images combined with long-slit, medium and high dispersion spectra of the southern planetary nebula (PN) NGC 5189. The complex morphology of this PN is puzzling and has not been studied in detailed so far. Our investigation reveals the presence of a new dense and cold infrared torus (alongside the optical one) which probably generated one of the two optically seen bipolar outflows and which might be responsible for the twisted appearance of the optical torus via an interaction process. The high-resolution MES-AAT spectra clearly show the presence of filamentary and knotty structures as well as three expanding bubbles. Our findings therefore suggest that NGC 5189 is a quadrupolar nebula with multiple sets of symmetrical condensations in which the interaction of outflows has determined its complex morphology.