The value-added catalogue of quiescent galaxies in the ALHAMBRA survey (VAQA) is a flux-limited collection of quiescent galaxies, along with their stellar population properties, defined after a detailed SED-fitting analysis. The VAQA catalogue contains the stellar population properties of ~16000 quiescent galaxies down to I≤23 over a redshift range of 0.1≤z≤1.1. All the stellar population properties (age, metallicity, extinction, luminosity, etc.) were constrained by making use of the fitting code for spectral energy distribution MUFFIT (MUlti-Filter FITting for stellar population diagnostics, Diaz-Garcia et al. 2015) and the multi-filter photometry from the ALHAMBRA survey. We adopted the ALHAMBRA Gold catalogue as the reference photometric catalogue, which is based on observations collected at the Centro Astronomico Hispano Aleman (CAHA) at Calar Alto (operated jointly by the Max-Planck Institut fur Astronomie and the Instituto de Astrofisica de Andalucia). In brief, the ALHAMBRA Gold catalogue provides photometric redshift constraints and flux in 20 top hat medium-bands in the optical range (~300Å width, λλ 3500—9700Å) and 3 in the near-infrared (J, H, and Ks; λλ 1.0—2.3 μ m) across 2.8 deg2 of the northern hemisphere.
To assess potential systematics from the use of different population synthesis models and perform the SED-fitting analysis, we built three independent sets of composite models (two burst models) from the simple stellar population models of Bruzual & Charlot (2003) (BC03, Padova1994 stellar tracks) and Vazdekis et al. (2016) (EMILES, Padova00 and BaSTI isochrones). The sample of quiescent galaxies was defined using a rest-frame stellar mass—colour diagram corrected for extinction (MCDE) to minimise the contamination of dusty star-forming galaxies. To increase the purity of the sample, we also carried out an individual inspection of all the red sources (simultaneously checking one-by-one all the galaxy stamps and the adequacy of the photometry and/or apertures), hence removing those galaxies whose photometry were compromised by very nearby sources, were imaged in bad CCD regions, or had spurious detections. In addition, a stellar SED-fitting analysis was performed for the removal of cool stars at faint magnitudes (22.5 ≤ I ≤ 23).
For the VAQA catalogue, we adopted a Lambda cold dark matter cosmology with H0=71 km s-1, ΩM=0.27, and ΩΛ=0.73. Stellar masses are quoted in solar mass units and magnitudes in the AB-system. The initial mass function of Chabrier (2003) and Kroupa (2001, universal) were assumed for the BC03 and EMILES SSP models, respectively. For the stellar mass completeness of the VAQA catalogue, we refer users to Sect.3.5 in Diaz-Garcia et al. (2019a). Dust attenuation was added as a foreground screen assuming a Fitzpatrick et al. (1999) extinction law, that is, we do not distinguish between attenuation and extinction during the dust modelling.
The VAQA catalogue is fully described in Diaz-Garcia et al. (2019a). The use of the VAQA catalogue requires citing the work by Diaz-Garcia et al. (2019a). The stellar population properties of the quiescent galaxies in the VAQA catalogue, as well as their evolution across cosmic time, were studied and detailed in Diaz-Garcia et al. (2019a), Diaz-Garcia et al. (2019b), and Diaz-Garcia et al. (2019c).
| Tool | What it Does | Use it when... |
|---|---|---|
| Quiescent Galaxies Search - qabc03 | Lets you search quiescent galaxies by position or name using the model qabc03. | You want to know the quiescent galaxies using the model qabc03. |
| Quiescent Galaxies Search - qapadova | Lets you search quiescent galaxies by position or name using the model qapadova. | You want to know the quiescent galaxies using the model qapadova. |
| Quiescent Galaxies Search - qabasti | Lets you search quiescent galaxies by position or name using the model qabasti. | You want to know the quiescent galaxies using the model qabasti. |
| V.O. Services | Lets you access to images and objects data through Virtual Observatory (V.O.) protocols using V.O. compatible applications. V.O. services offered are Simple Cone Search (SCS), Table Access Protocol (TAP), . | You want to use a V.O. compatible application to access catalogue data or images and you want to know the URL of the service. |
| V.O. Asynchronous Queries (ADQL) | Lets you search the database for all objects that meet any criteria you can think of, then returns whatever object data you request. Database queries are in Astronomical Data Query Language (ADQL), which is basically a standardised version of SQL (ADQL help and examples). | You want to answer a specific astronomical research question. |