Hempel, M.
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The VVV and VVVX survey: The inner Milky Way in the Near-Infrared
For almost exactly 13 years the combined VVV and VVVX survey collected data of the Milky Way Bulge and its adjacent Disk, in order to study the structure and stellar populations. Now, with the completion of both surveys, and in combination with other NIR programs we are just beginning to mine that treasure trove of data. Here I present some of the questions tackled by both surveys, and how the the data- especially their completeness, affect the study of the inner Milky Way.
Alonso, M. V.
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Galaxies behind the Galactic disk
The number of known galaxies decreases significantly at low galactic latitudes due to the presence of gas, dust and high stellar density from our Galaxy. This is an overview of our work in these regions using the near-IR images from the VISTA Variables in the Vía Láctea survey and some future perspectives.
Lebron Santos, M.
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New infrared galaxy candidates near the Ophiuchus supercluster
We study the extension of the Ophiuchus supercluster toward the dust-obscured Milky Way disk (ZoA) using the Spitzer GLIMPSE 3D archived data. A catalog of galaxy candidates from the northern galactic bulge was compiled. Three color images covering a 24 sq deg area were visually inspected for galaxy identification using selection criteria based on morphology at the 8 micron GLIMPSE 3D images, following Marleau et al. 2008 work. 119 galaxy candidates were selected for the final catalog. Each candidate was also searched for a counterpart in the ALLWISE catalog. The WISE colors of the sample were compared with color-color diagrams of galaxies in the ZoA with detected and non-detected HI. Most of the galaxies in our catalog share the WISE color-color space with the galaxies with detected HI. We require spectroscopic observation to determine the membership in the Ophiuchus supercluster of the galaxies in our sample. Ongoing HI surveys like Wallaby will be of great benefit to this project.
Galaz, G.
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The giant low surface brightness galaxy Malin 1: news for an amazing galaxy
I present new results for the stellar and stellar formation properties of the giant low surface brightness galaxy (gLSBG) Malin 1, obtained recently with the VLT/MUSE and GBT. I describe these results in the scope of the perplexing structural and stellar formation properties of Malin 1. These results, as well as other well-known properties of gLSBGs, represent a challenge for the galaxy formation models. I discuss this aspect too.
Minniti, D.
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The innermost region of the Milky Way
The VVVX survey is a near-IR survey of the southern disk and bulge of our Galaxy, made with the VISTA telescope at the ESO Paranal Observatory.
Over the past 12 years we have been mapping a large region that is severely affected by interstellar extinction using the JHKs filters, in order to unveil the internal structure of the Milky Way.
We have also observed repeatedly in the Ks-band, in order to reveal the variable sources along these obscured lines of sight.
In this talk I will describe the huge database that is a precious legacy for the community, and I will also focus on a few of the latest discoveries made by the VVVX survey team.
Marchant Cortés, P.
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Misclassifications of galaxies in the Zone of Avoidance using Machine Learning tools
Automated methods for classifying extragalactic objects in extensive surveys are essential for efficiency. However, the Zone of Avoidance (ZoA) presents significant challenges with dust extinction, star crowding, and limited data. Zhang et al. (2021) recently implemented machine learning techniques to classify stars, galaxies, and qso in the 4XMM-DR9, containing the ZoA. We investigate the challenges and advantages of using ML tools for galaxy classification in the ZoA and explore the implications of environmental factors on classification results and their reliability. Our analysis reveals significant differences between the sample galaxies and those present all over the Galactic disc, mainly due to the lack of information on galaxies in the Galactic plane in the training set. Some chosen regions within the ZoA exhibit a high probability of being a galaxy in X-ray data but they closely resemble extended Galactic objects. Our findings highlight the complexities of machine learning-based galaxy classification in the ZoA, emphasizing the need to consider environmental factors and refine data distribution for more robust future studies in this challenging region.
Véliz Astudillo, S.
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The effect of galaxy cluster dynamics on their populations and fundamental relations at low redshift
In the context of the standard cosmological model ΛCDM, massive galaxy clusters form hierarchically through merging and smooth accretion. The model predicts that numerous clusters of galaxies are in some stage of merging at any epoch. These processes are the most powerful events in the universe after the Big Bang, releasing energy at 10⁶⁴ erg/s, making them unique laboratories to study galaxy evolution. Under such conditions, galaxies may undergo violent processes that alter their physical properties and morphology.
In this study, by combining optical and X-ray data, we find that the dynamical state of low-redshift clusters (0.10 < z < 0.35) significantly impacts the physical and structural properties of their member galaxies differentially. Furthermore, we conclude that the dynamics of these systems also modify the mass-size relations, but not the red cluster sequence nor the morphology-density relation.
Lunch
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Pichel, A.
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Unveiling the enigma of missing blazars in the galactic plane
Blazars represent a distinct subtype of Active Galactic Nuclei (AGNs) and stand out as the most populous class of high- and very-high-energy gamma-ray sources. They rank among the most potent astronomical sources known to date, owing to their rapid, variable emissions and high luminosity across the entire electromagnetic spectrum. The task of compiling a comprehensive blazar sample across the entire sky encounters its most significant challenge at low galactic latitudes. In these regions, the presence of galactic dust and gas extinction, coupled with a high density of stars, hampers not only the identification of blazars but also subsequent studies on them. Consequently, the pursuit and identification of high-energy blazars within the galactic plane pose a highly intriguing challenge. In the course of this talk, I will provide an overview of gamma-ray astronomy, delving into the specifics of blazars and the methodologies employing near and mid-infrared techniques to facilitate their identification amidst the complexities of the galactic plane.
Oio, G.
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Outflows in IR selected AGNs
Active galactic nucleus (AGN) driven outflows can have a significant impact on the evolution of the host galaxy. In this presentation, I will compare the properties of galaxies that hosts AGNs with and without outflows. Our sample consists of 103 AGNs identified by mid-IR color-color selection, and confirmed with optical spectroscopy at a redshift range of 0.3 ≲ z ≲ 0.9. We fit the [O III] λ5007 line using spectra from the zCOSMOS survey to identify and to study the occurrence of outflows. We find that ionized outflows are present in ∼25% of our sample, with the largest incidence at the highest [O III] and X-ray luminosity bins. The fastest outflows are found in the more extended and massive galaxies. We do not observe a difference in the star formation rate of AGNs with outflows compared to AGNs without outflows. From visual inspection and non-parametric morphological studies, we obtain that outflows are preferentially observed in galaxies with disk-type and elliptical morphologies.
Carneiro, S.
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Active galactic nuclei and gravitational redshifts
Context. Gravitational redshift is a classical effect of Einstein’s General Relativity, already measured in stars, quasars and clusters of galaxies.
Aims. We here aim to identify the signature of gravitational redshift in the emission lines of active galaxies due to supermassive black holes, and compare to what is found for inactive galaxies.
Methods. Using the virial theorem, we estimate gravitational redshifts for quasars from the 14th data release of the Sloan Digital Sky Survey, and compare these with measured ones from the difference between the redshifts of emission lines of Sydney Australian Astronomical Observatory Multi-object Integral Field (SAMI) galaxies in central and outer annuli of their integral field spectra.
Results. Firstly, from the full width at half maximum of Hβ lines of 57 Seyfert type I galaxies of the AGN Black Hole Mass Database, we derive a median gravitational redshift zg = 1.18 × 10−4. Expanding this analysis to 86755 quasars from DR14 of SDSS we have a median value zg = 1.52 × 10−4 . Then, by comparing the redshifts of 34 lines measured at central and outer regions of LINER galaxies in the SAMI survey we obtain zg = (0.68 ± 0.09) × 10−4 , which increases to zg = (1.0 ± 0.1) × 10−4 when using Hα and Hβ lines. These numbers are compatible with central black holes of ≈ 10^9 solar masses and broad line regions of ≈ 1 pc. For non-AGN galaxies the gravitational redshift is compatible with zero.