Search Publications
Is HH 47 Slowing Down?
Velázquez, P. F.; Raga, A. C.; Noriega-Crespo, A.
We have used three epochs of red [S II] and Hα Hubble Space Telescope (HST) archival images of HH 47 to determine the proper motion velocities of the knots along the jet. With the three available epochs we compute two sets of proper motions (one using the first two epochs, and the second one using the last two epochs). Somewhat surprisingly, we fi…
The Time-Dependent Wavelet Spectrum of HH 1 and 2
Raga, A. C.; Esquivel, A.; Riera, A. +2 more
We have calculated the wavelet spectra of four epochs (spanning ≈20 yr) of Hα and [S II] HST images of HH 1 and 2. From these spectra we calculated the distribution functions of the (angular) radii of the emission structures. We found that the size distributions have maxima (corresponding to the characteristic sizes of the observed structures) wit…
The 2017 Release Cloudy
Abel, N. P.; Keenan, F. P.; Ferland, G. J. +8 more
We describe the 2017 release of the spectral synthesis code Cloudy, summarizing the many improvements to the scope and accuracy of the physics which have been made since the previous release. Exporting the atomic data into external data files has enabled many new large datasets to be incorporated into the code. The use of the complete datasets is …
Proper motions of the HH 1 jet
Velázquez, P. F.; Bally, J.; Raga, A. C. +9 more
We describe a new method for determining proper motions of extended objects, and a pipeline developed for the application of this method. We then apply this method to an analysis of four epochs of [S II] HST images of the HH 1 jet (covering a period of ≈20 yr). We determine the proper motions of the knots along the jet, and make a reconstruction o…
Infrared characteristics of the BIS catalog objects
Nesci, R.; Rossi, C.; Gaudenzi, S. +3 more
We studied several color-color infrared diagrams of the 276 late type stars of the BIS catalog. For 95 of these stars we derived spectral classification from our slit spectroscopy. From the 2MASS color diagram we concluded that none of the sample stars is a dwarf. The WISE 3.4-12 vs 12-22 plot is the best to discriminate the variability type (Mira…
Absolute Nuv magnitudes of Gaia DR1 astrometric stars and a search for hot companions in nearby systems
Makarov, V. V.
Accurate parallaxes from Gaia DR1 (TGAS) are combined with GALEX visual Nuv magnitudes to produce absolute Mnuv magnitudes and an ultraviolet HR diagram for a large sample of astrometric stars. A functional fit is derived of the lower envelope main sequence of the nearest 1403 stars (distance <40 pc), which should be reddening-free. Using this …
The IRAS 08589-4714 star-forming region
Gómez, M.; Rubio, M.; Cappa, C. E. +3 more
We present an analysis of the IRAS 08589-4714 star-forming region. This region harbors candidate young stellar objects identified in the WISE and Herschel images using color index criteria and spectral energy distributions (SEDs). The SEDs of some of the infrared sources and the 70 µm radial intensity profile of the brightest source are mode…
Spectral Properties and Variability of BIS objects
Nesci, R.; Rossi, C.; Gaudenzi, S. +3 more
Through the analysis and interpretation of newly obtained and of literature data we have clarified the nature of poorly investigated IRAS point sources classified as late type stars, belonging to the Byurakan IRAS Stars catalog. From medium resolution spectroscopy of 95 stars we have strongly revised 47 spectral types and newly classified 31 sourc…
A submillimeter study of the IR dust bubble S 21 and its environs
Rubio, M.; Borissova, J.; Firpo, V. +4 more
Based on the molecular emission in the 12CO(2-1) and 13CO(2-1) lines, and on the continuum emission in the MIR and FIR towards the S 21 IR dust bubble, we analyze the physical characteristics of the gas and dust linked to the nebula and the presence of young stellar objects (YSOs) in its environs. The line emission reveals a …
NGC 2440 : A morpho-kinematical model
Costa, R. D. D.; Lago, P. J. A.
The 3D structure and position-velocity (P-V) diagrams of NGC 2440 were modeled aiming to describe the morphology of this object, specially its core. High resolution spectra, HST images and P-V diagrams were used to reproduce the 3D structure of the nebula using SHAPE. The best model for the nebula is a torus torn apart in three pieces by interacti…