Preparing for LSST data

Abstract

Aims. We study how the upcoming Legacy Survey of Space and Time (LSST) data from the Vera C. Rubin Observatory can be employed to constrain the physical properties of normal star-forming galaxies (main-sequence galaxies). Because the majority of the observed LSST objects will have no auxiliary data, we use simulated LSST data and existing real observations to test the reliability of estimates of the physical properties of galaxies, such as their star formation rate (SFR), stellar mass (Mstar), and dust luminosity (Ldust). We focus on normal star-forming galaxies because they form the majority of the galaxy population in the universe and are therefore more likely to be observed with the LSST. Methods. We performed a simulation of LSST observations and uncertainties of 50 385 real galaxies within the redshift range 0 < z < 2.5. In order to achieve this goal, we used the unique multi-wavelength data from the Herschel Extragalactic Legacy Project (HELP) survey. Our analysis focused on two fields, ELAIS N1 and COSMOS. To obtain the physical properties of the galaxies, we fit their spectral energy distributions (SEDs) using the Code Investigating GALaxy Emission. We simulated the LSST data by convolving the SEDs fitted by employing the multi-wavelength observations. We compared the main galaxy physical properties, such as SFR, Mstar, and Ldust obtained from the fit of the observed multi-wavelength photometry of galaxies (from the UV to the far-IR) to those obtained from the simulated LSST optical measurements alone. Results. We present the catalogue of simulated LSST observations for 23 291 main-sequence galaxies in the ELAIS N1 field and for 9093 galaxies in the COSMOS field. It is available in the HELP virtual observatory. The stellar masses estimated based on the LSST measurements agree with the full UV to far-IR SED estimates because they mainly depend on the UV and optical emission, which is well covered by LSST in the considered redshift range. Instead, we obtain a clear overestimate of the dust-related properties (SFR, Ldust, Mstar) estimated with the LSST alone. They are highly correlated with redshift. We investigate the cause of this overestimate and conclude that it is related to an overestimate of the dust attenuation in both UV and near-IR. We find that it is necessary to employ auxiliary rest-frame mid-IR observations, simulated UV observations, or the far-UV attenuation (AFUV)-Mstar relation to correct for the overestimate. We also deliver the correction formula log10(SFRLSST/SFRreal) = 0.26 ⋅ z2 − 0.94 ⋅ z + 0.87. It is based on the 32 384 MS galaxies detected with Herschel.

Low-frequency Radio Continuum Imaging and SED Modeling of 11 LIRGs: Radio-only and FUV to Radio Bands

“…Therefore, different regimes of the broad SED provide critical insight into the nature, origin of emission, and factors that establish the energy balance. The astrophysical properties of galaxies using the Code Investigating GALaxy Emission (CIGALE) model set for main-sequence (normal) star-forming galaxies (Ciesla et al 2017;Vika et al 2017;Pearson et al 2018;Riccio et al 2021;Shirley et al 2021), LIRGs, and ULIRGs have been characterized (Małek et al 2017(Małek et al , 2018Paspaliaris et al 2021). As these galaxies can host AGNs, the CIGALE code includes the AGN component in the modeling.…”

New era of LSST data: Estimating the physical properties of main-sequence galaxies

“…By adding the rest-frame near infrared (IR) measurements the attenuation of the old stellar population would be better constrained, while the mid-and far-IR mainly constrain the dust emission from the star-forming regions and the SFR hidden by dust. Riccio (2021) showed that adding mid-IR or ultraviolet observations, along with LSST bands, the overestimation is completely corrected.…”

“…We then simulate the LSST observations according to the technical description of the future survey (Ivezic 2019) and perform the SED fitting. The detailed description of the methodology, used parameters, and test can be found in Riccio (2021).…”

Testing the key role of the stellar mass–halo mass relation in galaxy merger rates and morphologies via DECODE, a novel Discrete statistical sEmi-empiriCal mODEl

“…It can indeed rapidly probe galaxy merger rates, satellites abundances, morphologies, star formation histories for any given input SMHM relation and with minimal input parameters. will also constitute a very precious instrument for generating robust galaxy mock catalogues for the upcoming large-scale extra-galactic surveys such as Euclid (e.g., Scaramella et al 2021;Euclid Collaboration et al 2019, 2022 and LSST (e.g., Bridge et al 2009;Ptak & LSST Galaxies Collaboration 2011;Covey et al 2010;Gawiser et al 2013;Riccio et al 2021). subhaloes of that mass which cross the virial radius of the parent halo at that redshift.…”