Extracting H<i>α</i>flux from photometric data in the J-PLUS survey

Vilella-Rojo, G.; Viironen, K.; López-Sanjuan, C.; Cenarro, A. J.; Varela, J.; Díaz-García, L. A.; Cristóbal-Hornillos, D.; Ederoclite, A.; Marín-Franch, A.; Moles, M.

doi:10.1051/0004-6361/201526374

Cited by 31 publications

(46 citation statements)

References 38 publications

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“…In a recent study by Vilella-Rojo et al (2015), the authors find that Hα + [N ii] fluxes obtained with the combination of two filters are underestimated by 28% compared to the fluxes derived via SED fitting. It is important to take this into account when comparing fluxes calculated with different techniques.…”

Section: Line Flux and Line Luminosity Estimationmentioning

confidence: 99%

Properties of galaxies at the faint end of the Hαluminosity function atz~ 0.62

Gómez-Guijarro

Gallego

Villar

et al. 2016

A&A

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Context. Studies measuring the star formation rate density, luminosity function, and properties of star-forming galaxies are numerous. However, it exists a gap at 0.5 < z < 0.8 in Hα-based studies. Aims. Our main goal is to study the properties of a sample of faint Hα emitters at z ∼ 0.62. We focus on their contribution to the faint end of the luminosity function and derived star formation rate density, characterising their morphologies and basic photometric and spectroscopic properties. Methods. We use a narrow-band technique in the near-infrared, with a filter centred at 1.06 µm. The data come from ultra-deep VLT/HAWK-I observations in the GOODS-S field with a total of 31.9 h in the narrow-band filter. In addition to our survey, we mainly make use of ancillary data coming from the CANDELS and Rainbow Cosmological Surveys Database, from the 3D-HST for comparison, and also spectra from the literature. We perform a visual classification of the sample and study their morphologies from structural parameters available in CANDELS. In order to obtain the luminosity function, we apply a traditional V/V max method and perform individual extinction corrections for each object to accurately trace the shape of the function. Results. Our 28 Hα-selected sample of faint star-forming galaxies reveals a robust faint-end slope of the luminosity function α = −1.46 +0.16 −0.08 . The derived star formation rate density at z ∼ 0.62 is ρ SFR = 0.036 +0.012 −0.008 M yr −1 Mpc −3 . The sample is mainly composed of disks, but an important contribution of compact galaxies with Sérsic indexes n ∼ 2 display the highest specific star formation rates. Conclusions. The luminosity function at z ∼ 0.62 from our ultra-deep data points towards a steeper α when an individual extinction correction for each object is applied. Compact galaxies are low-mass, low-luminosity, and starburst-dominated objects with a light profile in an intermediate stage from early to late types.

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Section: Line Flux and Line Luminosity Estimationmentioning

confidence: 99%

Properties of galaxies at the faint end of the Hαluminosity function atz~ 0.62

Gómez-Guijarro

Gallego

Villar

et al. 2016

A&A

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“…In a previous work, Vilella-Rojo et al (2015) show that reliable Hα fluxes of star-forming regions in galaxies with z ≤ 0.015 can be recovered using the J-PLUS photometric data. In that redshift range, the Hα + [NII] emission is covered by the J0660 narrow band filter, and different methodologies were tested to extract the Hα emission from it.…”

Section: Extracting Hα Emission Line Fluxes From J-plus Photometric Datamentioning

confidence: 98%

“…The following step consists in retrieving the dust corrected Hα emission line flux of every star-forming region. The methodology designed by Vilella-Rojo et al (2015) to do it is briefly reviewed in the next section.…”

Section: Flux Meauserements From J-plus Datamentioning

confidence: 99%

“…The photometry in the twelve J-PLUS bands is required for this step; -Corrects the emission from dust extinction in the host galaxy, making use of a derived empirical relation based on the (gi) colour, obtained with SDSS data (eq. [20] in Vilella-Rojo et al 2015); -Removes the [NII] contribution and isolates the Hα emission line flux with another derived empirical relation based on the (gi) colour as well (eq. [21] in Vilella-Rojo et al 2015).…”

Section: Extracting Hα Emission Line Fluxes From J-plus Photometric Datamentioning

confidence: 99%

“…In a previous work, Vilella-Rojo et al (2015) predict, using synthetic photometry, that unbiased Hα fluxes from star-forming regions can be retrieved using the J-PLUS photometric system. The goal of the present paper is to test and validate the methodology presented by Vilella-Rojo et al (2015) with real data, comparing the J-PLUS measurements with spectroscopic Hα emission line fluxes from the literature. SDSS and CALIFA were chosen so the comparison is performed with both spectroscopic fiber and integral field spectroscopic data, and because both datasets contain galaxies at z ≤ 0.015.…”

Section: Introductionmentioning

confidence: 99%

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J-PLUS: Measuring Hα emission line fluxes in the nearby universe

Logroño-García

Vilella-Rojo

López-Sanjuan

et al. 2019

A&A

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In the present paper we aim to validate a methodology designed to extract the Hα emission line flux from J-PLUS photometric data. J-PLUS is a multi narrow-band filter survey carried out with the 2 deg 2 field of view T80Cam camera, mounted on the JAST/T80 telescope in the OAJ, Teruel, Spain. The information of the twelve J-PLUS bands, including the J0660 narrow-band filter located at rest-frame Hα, is used over 42 deg 2 to extract de-reddened and [NII] decontaminated Hα emission line fluxes of 46 star-forming regions with previous SDSS and/or CALIFA spectroscopic information. The agreement of the inferred J-PLUS photometric Hα fluxes and those obtained with spectroscopic data is remarkable, with a median comparison ratio R = F J−PLUS Hα /F spec Hα = 1.05 ± 0.25. This demonstrates that it is possible to retrieve reliable Hα emission line fluxes from J-PLUS photometric data. With an expected area of thousands of square degrees upon completion, the J-PLUS dataset will allow the study of several star formation science cases in the nearby universe, as the spatially resolved star formation rate of nearby galaxies at z ≤ 0.015, and how it is influenced by the environment, morphology or nuclear activity. As an illustrative example, the close pair of interacting galaxies NGC3994 and NGC3995 is analyzed, finding an enhancement of the star formation rate not only in the center, but also in outer parts of the disk of NGC3994.

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Star-forming galaxies at low-redshift in the SHARDS survey

Lumbreras-Calle

Muñoz–Tuñón

Méndez-Abreu

et al. 2019

A&A

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Context. The physical processes driving the evolution of star formation (SF) in galaxies over cosmic time still present many open questions. Recent galaxy surveys allow now to study these processes in great detail at intermediate redshift (0 ≤ z ≤ 0.5). Aims. We build a complete sample of star-forming galaxies and analyze their properties, reaching systems with low stellar masses and low star formation rates (SFRs) at intermediate-to-low redshift. Methods. We use data from the SHARDS multiband survey in the GOODS-North field. Its depth (up to magnitude m 3σ ∼ 26.5) and its spectro-photometric resolution (R ∼ 50) provides us with an ideal dataset to search for emission line galaxies (ELGs). We develop a new algorithm to identify low-redshift (z<0.36) ELGs by detecting the [OIII]5007 and Hα emission lines simultaneously. We fit the spectral energy distribution (SED) of the selected sample, using a model with two single stellar populations. Results. We find 160 star-forming galaxies for which we derive equivalent widths (EWs) and absolute fluxes of both emission lines. We detect EWs as low as 12 Å, with median values for the sample of ∼ 35 Å in [OIII]5007 and ∼ 56 Å in Hα, respectively. Results from the SED fitting show a young stellar population with low median metallicity (36% of the solar value) and extinction (A V ∼ 0.37), with median galaxy stellar mass ∼ 10 8.5 M . Gas-phase metallicities measured from available spectra are also low. ELGs in our sample present bluer colours in the UVJ plane than the median colour-selected star-forming galaxy in SHARDS. We suggest a new (V-J) colour criterion to separate ELGs from non-ELGs in blue galaxy samples. In addition, several galaxies present high densities of O-type stars, possibly producing galactic superwinds, which makes them interesting targets for follow-up spectroscopy. Conclusions. We have demonstrated the efficiency of SHARDS in detecting low-mass ELGs (∼2 magnitudes deeper than previous spectroscopic surveys in the same field). The selected sample accounts for 20% of the global galaxy population at this redshift and luminosity, and is characterized by young SF bursts with sub-solar metallicities and low extinction. However, robust fits to the full SEDs can only be obtained including an old stellar population, suggesting the young component is built up by a recent burst of SF in an otherwise old galaxy.

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Extracting Hαflux from photometric data in the J-PLUS survey

Cited by 31 publications

References 38 publications

Properties of galaxies at the faint end of the Hαluminosity function atz~ 0.62

Properties of galaxies at the faint end of the Hαluminosity function atz~ 0.62

J-PLUS: Measuring Hα emission line fluxes in the nearby universe

Star-forming galaxies at low-redshift in the SHARDS survey

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