J-PLUS: The planetary nebula population of M 33

TL;DR

This study addresses the challenge of detecting and characterizing extragalactic planetary nebulae in M33 using the multi-band J-PLUS DR3 dataset. By applying SExtractor and PSFEx on 12-band images across three fields, the authors recover 98 known PNe (including 13 previously cataloged in J-PLUS) and derive photometry in all bands, then use diagnostic color-color diagrams and available kinematic data to assess halo membership. The analysis reveals that many PNe share halo-like colors, but contaminants such as H II regions and clusters dominate; after imposing an FWHM size constraint, only one candidate remains plausible as a halo PN, implying a disk-dominated PN population in M33. The work demonstrates the feasibility and limitations of multi-band photometric surveys for extragalactic PNe and informs strategies for future surveys like J-PAS, which will offer additional filters (notably [O III]) and greater depth to enable cleaner PN selection and census in nearby galaxies.

Abstract

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.

Figures (8)

• Figure 1: J-PLUS transmission curves superposed with the spectrum of a planetary nebula selected by VPHAS+ and ALLWISE color criteria and spectroscopically confirmed liberato+23. It is possible to see the H$\alpha$ emission in the spectrum (black line) falling over the $J0660$ filter, as indicated in the label. The [O iii] duplet is also visible, at the edge of the filter $J0515$.
• Figure 2: The three H$\alpha$ J-PLUS fields of view selected to cover the M 33 galaxy. J-PLUS images 04327, 04326 and 04283, with central coordinates (RA,Dec) of 23.9935,31.1133, upper left), 22.3818,31.1133, upper right and 23.2496,29.7209, bottom, respectively. Each image is $\approx$ 2 deg$^{2}$. The markers represent the 143 PNe, being in blue the 98 PNe we recovered, in red the 45 missing and the 13 ones already catalogued on J-PLUS are marked in yellow. North is up, east to the left.
• Figure 3: MAG_AUTO vs FLUX_RADIUS space used to select point-sources for the PSF model. In red are shown the selected ones, leaving out the nearly horizontal line in the upper part of the plot that can comprise saturated sources. The population of fainter magnitudes are extended or spurious sources, like cosmic rays.
• Figure 4: H$\alpha$ M 33 mosaic image made with the three J-PLUS fields. The markers represent extracted sources that pass through the hPNe criteria for the MW halo gutierrez-soto19 that will be discussed in Section 3.1, being the yellow ones confirmed PNe magrini00ciardullo04galera-rosillo18 and the magenta possible PN candidates. North is up, east to the left. The image has a size of $\approx$ 1 degree.
• Figure 5: Left: DCCDs showing the extracted sources from the field images in gray and in dark purple the sources that passes all the criteria from gutierrez-soto19, represented as black lines. The extracted PNe are shown in red, except for 5 of them in yellow representing the ones that pass all the criteria at the same time, and the one in light blue representing one PN that according to ciardullo04 might be a halo PNe. Right: Distribution of the selected objects in each DCCDs.