Fuerzas no gravitacionales en cometas de largo período

Se estudia el efecto de fuerzas no gravitacionales sobre cometas de largo período, en particular en lo que concierne a la perturbación de la energía orbital. De la comparación de resultados computacionales, derivados a partir de la integración numérica de órbitas de cometas ficticios, con la muestra observada de cometas de largo período, surge como valor probable de la magnitud de la aceleración no gravitacional: 10⁻⁸ UA dia⁻². Este valor resulta ser 1 - 2 órdenes de magnitud mayor que los valores típicos deducidos para los cometas de corto período. Estos resultados pueden interpretarse en términos de una mayor actividad de los cometas nuevos o dinámicamente jóvenes, en relación a los cometas de corto período, asociada a una fracción mayor de superficie cometaria conteniendo volátiles expuestos a la radiación solar.Asociación Argentina de Astronomí

CO, 13CO and [CI] in Galaxy Centers

Measurements of [CI], (J=2-1) 13CO and (J=4-3) 12CO emission from quiescent, starburst and active galaxy centers reveal a distinct pattern characterized by relatively strong [CI] emission. The [CI] to 13CO emission ratio increases with central [CI] luminosity. It is lowest in quiescent and mild starburst centers and highest for strong starburst centers and active nuclei. Neutral C abundances are close to, or even exceed, CO abundances. The emission is characteristic of warm and dense gas rather than either hot tenuous or cold very dense gas. The relative intensities of CO, [CI], [CII] and far-infrared emission suggest that the dominant excitation mechanism in galaxy centers may be different from that in Photon-Dominated Regions (PDRs).Comment: 6 pages, to appear in the Proceedings of the 2004 European Workshop: "Dense Molecular Gas around Protostars and in Galactic Nuclei", Eds. Y.Hagiwara, W.A.Baan, H.J.van Langevelde, 2004, a special issue of ApSS, Kluwe

An analysis of the FIR/RADIO Continuum Correlation in the Small Magellanic Cloud

The local correlation between far-infrared (FIR) emission and radio-continuum (RC) emission for the Small Magellanic Cloud (SMC) is investigated over scales from 3 kpc to 0.01 kpc. Here, we report good FIR/RC correlation down to ~15 pc. The reciprocal slope of the FIR/RC emission correlation (RC/FIR) in the SMC is shown to be greatest in the most active star forming regions with a power law slope of ~1.14 indicating that the RC emission increases faster than the FIR emission. The slope of the other regions and the SMC are much flatter and in the range of 0.63-0.85. The slopes tend to follow the thermal fractions of the regions which range from 0.5 to 0.95. The thermal fraction of the RC emission alone can provide the expected FIR/RC correlation. The results are consistent with a common source for ultraviolet (UV) photons heating dust and Cosmic Ray electrons (CRe-s) diffusing away from the star forming regions. Since the CRe-s appear to escape the SMC so readily, the results here may not provide support for coupling between the local gas density and the magnetic field intensity.Comment: 19 pages, 7 Figure

VERTICO. IV. Environmental effects on the gas distribution and star formation efficiency of Virgo cluster spirals

GalaxiesInterstellar matter and star formatio

The 30 doradus molecular cloud at 0.4 pc resolution with the atacama large millimeter/submillimeter array: physical properties and the boundedness of CO-emitting structures

Large scale structure and cosmolog

VERTICO: The Virgo Environment Traced in CO Survey

Galaxie

Star clusters near and far; tracing star formation across cosmic time

© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00690-x.Star clusters are fundamental units of stellar feedback and unique tracers of their host galactic properties. In this review, we will first focus on their constituents, i.e.\ detailed insight into their stellar populations and their surrounding ionised, warm, neutral, and molecular gas. We, then, move beyond the Local Group to review star cluster populations at various evolutionary stages, and in diverse galactic environmental conditions accessible in the local Universe. At high redshift, where conditions for cluster formation and evolution are more extreme, we are only able to observe the integrated light of a handful of objects that we believe will become globular clusters. We therefore discuss how numerical and analytical methods, informed by the observed properties of cluster populations in the local Universe, are used to develop sophisticated simulations potentially capable of disentangling the genetic map of galaxy formation and assembly that is carried by globular cluster populations.Peer reviewedFinal Accepted Versio

PHANGS-ALMA data processing and pipeline

Instrumentatio

Using CO to Measure Molecular Masses

With an increased appreciation for the role of gas in galaxy evolution, there is renewed interest in measuring gas masses for galaxies. I review some of the basic concepts in using CO to determine molecular masses, and discuss some of the recent work