Search Publications
A Peculiar Galaxy Near M104
Quiroga, E.
Messier 104, NGC 4594, also known as the Sombrero Galaxy, has been extensively studied, especially its structure and stellar halo. Its abundance of globular clusters has given rise to many theories and much speculation. However, other objects in the vicinity of such a spectacular galaxy are sometimes ignored. While studying HST images available on…
Temperature Discrepancy with Photoionization Models of the Narrow-Line Region
Binette, L.; Villar Martín, M.; Magris C., G. +4 more
Using published work on the narrow-line region of Active Galactic Nuclei, a comparison is carried out among the [OIII] λ4363Å/5007Å ratios (ROIII) observed in quasars, Seyfert 2's and the spatially resolved ENLR plasma. Using the weak [ArIV] λ4711Å/λ4740Å doublet observed by Koski (1978) among Seyfert 2's, we find …
C,T1,T2: A Complementary Method to Detect Multiple Populations with the Washington Filter System
Geisler, D.; Villanova, S.; Frelijj, H. +1 more
In this research we test the ability of a three Washington filter combination, (C − T1) − (T1 − T2), compared with that of the traditional C − T1 color to find multiple populations on two globular clusters: NGC 7099 and NGC 1851, types I and II Globular clusters, respectively. Our improved photometry and…
Hα Kinematics of the Isolated Interacting Galaxy Pair KPG 486 (NGC 6090)
Rosado, M.; Sánchez-Cruces, M.; Sardaneta, M. M.
In optical images, the barely studied isolated interacting galaxy pair KPG 486 (NGC 6090) displays similar features to the Antennae (NGC 4038/39) galaxy pair. To compare the distribution of ionized hydrogen gas, morphology and kinematic and dynamic behaviour of both galaxy pairs, we present observations in the Hα emission line of NGC 6090 acquired…
The HH34 Jet/Counterjet System at 1.5 and 4.5µm
Raga, A. C.; Noriega-Crespo, A.; Reipurth, B.
We present a (previously unpublished) 1.5 µm archival HST image of the HH 34 Herbig-Haro jet, in which the northern counterjet is seen at an unprecedented angular resolution of ≈0.1" (this counterjet had only been imaged previously at lower resolution with Spitzer). The jet/counterjet structure observed in this image shows evidence of low-am…
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…
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…
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…
Variability of the emission line fluxes and ratios of HH 1/2
Raga, A. C.; Reipurth, B.; Castellanos-Ramírez, Bally, J.
We compare spectrophotometric data of HH 1 and 2 obtained in 1978 (by Brugel et al. 1981a) with the emission line fluxes from calibrated Hubble Space Telescope (HST) images obtained in 1994 and 2014. This comparison shows that the emission line ratios of these objects have remained surprisingly invariant during the past 36 years. On the other hand…