arXiv subjects

Giovanna Liberato

Publications and source records attributed to Giovanna Liberato.

2 recordsLinked to original sources

arXiv2026

J-PLUS: The planetary nebula population of M 33

In this pilot study, we investigate the PN population in M~33, a nearby spiral galaxy ($\simeq 840$~kpc), using data from the DR3 of the Javalambre-Photometric Local Universe Survey (J-PLUS), a 12-band photometric dataset extensively used to identify H$α$ line emitters. From the 143 known PNe of M~33, the photometry of only 13 are present in the J-PLUS catalog, as available on the J-PLUS portal. With the aim of recovering a larger fraction of the M~33 PN population, the software SExtractor is adopted to extract the sources in the J-PLUS images and obtain the photometric data for the PNe known in the literature, performing PSF photometry when possible. With this procedure the photometry of 98 PNe was obtained using H$α$ image as detection image, including the 13 already present in the J-PLUS catalog. Using diagnostic color-color diagrams (DCCDs) based on criteria developed for Milky Way halo PNe, we identified 16 sources with PN-like colors. Cross-match with existing catalogs revealed that most of these candidates are H II regions, though one source remains unidentified. Additionally, analyzing their full width at half maximum, most of them would not be PN candidates. This highlights the method's ability to select emission-line objects but also underscores the challenge of distinguishing PNe from contaminants using photometry alone. The J-PLUS colors of 98 known PNe were analyzed, together with literature information on their radial velocities, resulting in the identification of one possible halo PN. This is the first paper which aims at detecting extragalactic PNe in multi-band surveys such as J-PLUS, the Southern Local Universe Survey (S-PLUS) and the Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS), paving the way for similar studies in these surveys for other nearby galaxies, which lack catalogs of known PNe.

astro-ph.GA↗

arXiv2023

Photometric candidate selection and spectroscopic confirmation of new PNe and SySts in the Galactic plane

About 3,500 planetary nebulae (PNe) are currently known in the Milky Way, which shows a great discrepancy with the expected number for these objects, regardless of the reference used, $33-59 \times 10^{3}$. The same holds for symbiotic stars (SySts) as well, since the expected number in the Galaxy ($3-400 \times 10^{3}$) differs considerably from the amount of known ones (approximately 300). Studies on PNe and SySts are of great importance because they provide vital clues to the understanding of the late-stage of stellar evolution for low-to-intermediate mass stars. In addition, these classes of objects play a large role in the chemical evolution of the Galaxy through the ejection of their material to the interstellar medium (ISM), enriching it with the various chemical elements produced throughout their evolution. This project aims to contribute to the detection of new PNe and SySts in the Galaxy, thus decreasing the discrepancy between the observed and theoretical populations. Using simultaneously the third data release from the optical survey VPHAS+ (The VST Photometric H$α$ Survey of the Southern Galactic Plane and Bulge), which maps the southern hemisphere of the Galaxy's plane with the $r$, $i$, and H{$α$} filters, and the IR colors of the catalog AllWISE (Wide-field Infrared Survey Explorer + The Two Micron All Sky Survey), we end up with a number of PN and SySt candidates. Subsequently, we confirm the nature of these objects through spectroscopic observations at the SOAR telescope (Southern Astrophysical Research Telescope). So far, we have selected PN candidates and performed the spectroscopic follow-up of 8 of them. In this presentation we show the project's preliminary results, which consist of the discovery of at least one new planetary nebula, and other emission-line sources still to be confirmed either as PN or SySt.

astro-ph.GA↗