Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

J-PLUS Reconstructing the Milky Way Disc's star formation history with twelve-filter photometry

J. A. Alzate-Trujillo, A. del Pino, C. López-Sanjuan, A. Hidalgo, S. Turrado-Prieto, Vinicius Placco, Paula Coelho, Haibo Yuan, Luis Lomelí-Núñez, Gustavo Bruzual, F. Jiménez-Esteban, Eduardo Telles, Borja Anguiano, Alvaro Alvarez-Candal, A. J. Cenarro, D. Cristóbal-Hornillos, C. Hernández-Monteagudo, A. Marín-Franch, M. Moles, J. Varela, H. Vázquez Ramió, J. Alcaniz, R. A. Dupke, A. Ederoclite, L. Sodré, R. E. Angulo

Abstract

Wide-field, multi-filter photometric surveys enable the reconstruction of the Milky Way's star formation history (SFH) on Galactic scales and offer new insights into disc assembly. The twelve-filter system of the Javalambre Photometric Local Universe Survey (J-PLUS) is particularly suitable, as its colours trace stellar chemical abundances and help alleviate the age-metallicity degeneracy in colour-magnitude diagram fitting. We aim to recover the SFH of the Galactic disc and separate its chemically distinct components by combining J-PLUS DR3 photometry with Gaia astrometry. We also evaluate the potential of isochrone fitting to estimate stellar ages and metallicities as proxies for evolutionary trends. We fit magnitudes and parallaxes of $1.38\times10^{6}$ stars using a Bayesian multiple isochrone method. The bright region of the colour-absolute-magnitude diagram ($M_{r}\leq4.2$ mag) constrains ages, while the faint region provides an empirical metallicity prior mitigating the age-metallicity degeneracy. Both PARSEC and BaSTI isochrones, in solar-scaled and $α$-enhanced forms, are adopted. The recovered SFH reveals two sequences: an $α$-enhanced population forming rapidly between $12.5$ and $8$ Gyr ago, enriching from [M/H]$\sim-0.6$ to $0.1$ dex; and a solar-scaled sequence emerging $\sim8$ Gyr ago, dominating after $\sim7$ Gyr with slower enrichment reaching solar metallicity by $3$ Gyr. Metal-rich ([M/H]$\gtrsim0$) stars are confined to $\vert z_{GC}\vert\lesssim1$ kpc, whereas metal-poor ([M/H]$\lesssim-0.5$) stars reach $\vert z_{GC}\vert\sim2$ kpc. Simultaneous fitting of both isochrone families reveals distinct formation epochs for the thin and thick discs. J-PLUS multi-filter photometry, combined with Gaia parallaxes, mitigates age-metallicity degeneracies and enables detailed mapping of the Milky Way's temporal and chemical evolution.

J-PLUS Reconstructing the Milky Way Disc's star formation history with twelve-filter photometry

Abstract

Wide-field, multi-filter photometric surveys enable the reconstruction of the Milky Way's star formation history (SFH) on Galactic scales and offer new insights into disc assembly. The twelve-filter system of the Javalambre Photometric Local Universe Survey (J-PLUS) is particularly suitable, as its colours trace stellar chemical abundances and help alleviate the age-metallicity degeneracy in colour-magnitude diagram fitting. We aim to recover the SFH of the Galactic disc and separate its chemically distinct components by combining J-PLUS DR3 photometry with Gaia astrometry. We also evaluate the potential of isochrone fitting to estimate stellar ages and metallicities as proxies for evolutionary trends. We fit magnitudes and parallaxes of stars using a Bayesian multiple isochrone method. The bright region of the colour-absolute-magnitude diagram ( mag) constrains ages, while the faint region provides an empirical metallicity prior mitigating the age-metallicity degeneracy. Both PARSEC and BaSTI isochrones, in solar-scaled and -enhanced forms, are adopted. The recovered SFH reveals two sequences: an -enhanced population forming rapidly between and Gyr ago, enriching from [M/H] to dex; and a solar-scaled sequence emerging Gyr ago, dominating after Gyr with slower enrichment reaching solar metallicity by Gyr. Metal-rich ([M/H]) stars are confined to kpc, whereas metal-poor ([M/H]) stars reach kpc. Simultaneous fitting of both isochrone families reveals distinct formation epochs for the thin and thick discs. J-PLUS multi-filter photometry, combined with Gaia parallaxes, mitigates age-metallicity degeneracies and enables detailed mapping of the Milky Way's temporal and chemical evolution.

Paper Structure

This paper contains 30 sections, 15 equations, 16 figures, 5 tables.

Table of Contents

  1. Introduction
  2. Data
  3. Modeling the colour-absolute-magnitude diagram
  4. Bayesian inference
  5. Stellar evolution model
  6. Sampling the CAMD
  7. Building the SFH
  8. Mitigating degeneracies with multi-filter photometry
  9. Estimating uncertainties
  10. Results
  11. Metallicity distribution of the MS low-mass stars
  12. Star formation history: solar-scaled and $\alpha$-enhanced models
  13. Simultaneous fitting of Solar-scaled and $\alpha$-enhanced models
  14. Spatially mapping metallicity and age gradients
  15. Young and Intermediate-age Populations ($<7$ Gyr)
  16. ...and 15 more sections

Figures (16)

  • Figure 1: Cumulative counts of the JP$\times$G , JP$\times$G$_{\rm 5 kpc}$ and JP$\times$G$_{\rm 5 kpc}$ ($J0378<0.1$ mag) samples. The dash-dotted and dashed lines point out the limits $r=16.5$ mag and $r=17.1$ mag, where the JP$\times$G$_{\rm 5 kpc}$ and JP$\times$G$_{\rm 5 kpc}$ ($J0378<0.1$ mag) counts drops $10\%$ below the JP$\times$G counts.
  • Figure 2: Hess diagram of the JP$\times$G$_{\rm 5kpc}^{r16.5}$ sample for a) $J0378-J0861$ and b) $u-i$. Panel c) shows the distribution of stars in the ($r$ vs $z_{GC}$) plane. The stellar colours and magnitudes are corrected by the effect of dust green18schafly11. The dotted horizontal line indicates the absolute $r$ magnitude equals to 4.2 mag, separating the regions we used to extract the information of ages and metallicities. The arrow illustrates the dimming and reddening vector corresponding to $A_{V}=1$ mag. The crosses arranged vertically show the colour and magnitude average errors, computed for all star within interval of size $\Delta r = 1$ mag.
  • Figure 3: J-PLUS magnitude differences between solar-scaled and $\alpha$-enhanced BaSTI models for MSTO stars. We selected three stellar pairs at $[{\rm M}/{\rm H}] = -0.1$ dex, with approximate ages of 2.5, 5.0 and 10 Gyr, and corresponding masses of 1.3, 1.1, and 1.0 M$_\odot$, respectively. The horizontal dashed line indicates the upper limit of the median absolute magnitude error, as averaged from the third column of Table \ref{['tab:stats']}.
  • Figure 4: Illustrative isochrone plot. Panel (a) displays a grid of 9 isochrones with ages of $2.5$, $5$, and $10$ Gyr, and metallicities of $[{\rm M}/{\rm H}] = -0.5$, $-0.2$, and $0.1$ dex. Isochrones with the same age are shown in green tones, illustrating the sensitivity of age and metallicity at the MSTO and the RGB phases. Panel (b) highlights the region of the CAMD where age sensitivity is highest ( dashed polygon), using three isochrones of the same metallicity ($[{\rm M}/{\rm H}]=-0.2$ dex). The double-headed red arrow indicates the magnitude separation used to quantify the average distance between isochrones. Panel (c) shows the same grid as (a), but with orange tones indicating isochrones of the same metallicity. Panel (d) shows three isochrones of the same age (5 Gyr), illustrating how magnitude and colour vary with metallicity. The cyan arrow indicates the magnitude separation used to define the average distance between isochrones.
  • Figure 5: Inferred metallicity distribution of the JP$\times$G$_{\rm 5kpc}^{r16.5}$ sample (solid histogram) for stars with absolute $r$ magnitudes fainter than 4.2 mag, using Grid A from Table\ref{['tab:iso']}. The dash-dotted line shows the metallicity distribution of an APOGEE DR17 sample, selected as described in Appendix \ref{['app:apo_samp']}. The dashed line indicates the normal function adopted as the prior on $[{\rm M}/{\rm H}]$ for the PARSEC models.
  • ...and 11 more figures