Presentations

Orador: Rodrigo Facundo Haack

Titulo: Galaxy properties in the Eridanus-Fornax-Doradus filament with S-PLUS + LePhare (Video)

Resumen: In the context of the S-PLUS Fornax Project (S+FP), we have obtained an extragalactic catalog containing homogeneous photometry for ~ 65,000 galaxies located, in projection, in the direction of the Fornax cluster, covering a sky area of ~ 208 square degrees around NGC 1399. A key problem to be solved in order to identify possible substructures in the spatial distribution of the objects included in that catalog, is to reliably determine their redshifts. In this talk we will present the strategy used to obtain the Extragalactic Catalog of the S+FP which involved the application of Machine Learning (ML) and Deep Learning (DL) techniques on a total of 3 x 10^6 resolved and unresolved sources, to identify and remove spurious objects and to perform a star/galaxy separation. From the application to this catalog of template fitting techniques, we were able to obtain preliminary photometric redshifts using the photometry in the 12 bands of S-PLUS, complemented with GALEX, VHS-Vista and WISE data. As a starting point, we expect such information allows us to differentiate, at least with some degree of confidence, background objects from possible Fornax members. This work represents the initial steps of my PhD Thesis, which proposes the study of the Doradus-Fornax-Eridanus filament with S-PLUS images.

Oradora: Amanda Reis Lopes

Titulo: Studying Emission Line Sources with S-PLUS (Video)

Resumen: The analysis of emission lines in astrophysical sources enables us to gain insight into the nature of the object, such as the density of the ionizing gas. Furthermore, the emission map associated with the HI image can provide us with a better understanding of the physical processes occurring in these sources. The filter configuration of the Southern Photometric Local Universe Survey (S-PLUS), a wide field 12 band (5 broad and 7 narrow) survey observing the Southern Sky, is ideal to detect emission by the combination of narrow and broad bands. To investigate Halpha emitters sources, we developed a code named P.E.L.E. (Pixel-to-pixel Emission Line Estimate) that combines S-PLUS images using the Three Filter Method to create emission line maps. We selected galaxies from the Fornax cluster to evaluate P.E.L.E., as the Halpha line is situated in the J0660 band at Fornax distance and there are already a few published Halpha maps from the Fornax 3D project that can be compared to our results. A second method to detect emission relies in the combination of color-color plots, which is efficient to search for Extreme Emission Line Galaxies (EELGs), which are low-metallicity star-forming galaxies that can be regarded as local analogs of galaxies in the early Universe. In this talk, we will discuss our two methodologies to identify emission, the first focus on the Fornax members and some preliminary tests on planetary nebulae in the Small Magellanic Cloud, and the second used to identify EELG at z less than 0.05.

Miércoles 14/12/2022 - 13:00 hs (Salón Meridiano)

Oradora: Amanda Reis Lopes (IALP, CONICET-UNLP, Argentina)

Título: Emission line galaxies with S-PLUS (Video)

Resumen: Emission lines in galaxies are valuable sources of information, allowing the analysis of star formation activity and the presence of active galactic nuclei, among others. The filter configuration of S-PLUS, a wide field 12 band (5 broad and 7 narrow) survey observing the Southern Sky, is ideal to detect emission by the combination of narrow and broad bands. In this talk, I will present two of my main topics of research: the investigation of Halpha emitters in higher density environments and the detection of Extreme emission line galaxies (EELGs), which are low-metallicity star-forming galaxies that can be regarded as local analogs of galaxies in the early Universe. For the first case, the Fornax cluster is a great target to perform an emission analysis, as Halpha is located in the J0660 band and its proximity provides large enough galaxies to study their emission spatial distribution. A code that applies the Three Filter Method to S-PLUS images to create emission line maps for Fornax members was developed. For the second topic, I will discuss the approach and results from my search for EELGs at z<0.05 using S-PLUS. The methodology relies in the combination of color-color plots to search for EELGs in a specific range of redshift, i.e. [OIII] emitters at z<0.05 present an excess in J0515 band, and Halpha emitters at z < 0.019 have an excess in J0660 band in comparison with broad band filters.

Miércoles 23/11/2022 - 13:00 hs (Salón Meridiano) 

Orador: Luis Ángel Gutiérrez Soto (IALP, CONICET-UNLP, Argentina)

Título: Herramientas para descubrir nuevos objetos con líneas de emisión en relevamientos fotométricos ópticos multibanda (Video)

Resumen: En la era de los grandes relevamientos fotométricos, una gran cantidad de datos han sido producidos y se continúan generando, permitiendo la identificación de nuevos objetos astrofísicos de diversa naturaleza. En este orden de ideas, los relevamientos fotométricos J-PAS, J-PLUS y su contraparte sur, S-PLUS, nos están proporcionando una cantidad de datos únicos, dado que J-PAS obtiene imágenes en 56 filtros de banda angosta, mientras que J-PLUS y S-PLUS lo hacen en 7 filtros de banda angosta y 5 de banda ancha. Hasta el momento, S-PLUS y J-PLUS, juntos, han mapeado ~5,000 deg2 del cielo en dirección del halo Galáctico posibilitando la identificación en el cielo norte y sur de objetos tan interesantes y fundamentales como fuentes con líneas de emisión. Ejemplos de dichas fuentes lo constituyen las nebulosas planetarias, las cuales representan la fase final de estrellas de baja masa y masa intermedia, así como algunos sistemas binarios, tales como estrellas simbióticas y variables cataclísmicas, las cuales pueden ser fácilmente identificadas en estos relevamientos gracias a la presencia de intensas líneas de emisión en sus espectros como ser la línea de Halfa. Usamos espectros sintéticos y observados para enfatizar el potencial de los diagramas color-color para distinguir en estos relevamientos varias clases de emisores, que incluyen nebulosas planetarias, regiones HII, objetos estelares jóvenes, sistemas estelares simbióticos, variables cataclísmicas, AGN y cuásares, entre otros. Además, se ha abordado un enfoque de aprendizaje automático (machine learning) supervisado y no supervisado, para distinguir diferentes clases de objetos con líneas de emisión. Las herramientas fueron validadas encontrando las coincidencias de los objetos seleccionados en bases de datos como SIMBAD y a través de espectroscopía.