Person: Alcalde Pampliega, Belén
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First Name
Belén
Last Name
Alcalde Pampliega
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Física de la Tierra y Astrofísica
Area
Física de la Tierra
Identifiers
8 results
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Item Shards: a global view of the star formation activity at z ~ 0.84 and z ~ 1.23(Astrophysical journal, 2015) Pérez González, Pablo Guillermo; Eliche Moral, María del Carmen; Alcalde Pampliega, Belén; Cardiel López, Nicolás; Domínguez Sánchez, Helena; Espino Briones, Néstor; Esquej Alonso, María del Pilar; Gallego Maestro, Jesús; Rodríguez Muñoz, LucíaIn this paper, we present a comprehensive analysis of star-forming galaxies (SFGs) at intermediate redshifts (z ~ 1). We combine the ultra-deep optical spectro-photometric data from the Survey for High-z Absorption Red and Dead Sources (SHARDS) with deep UV-to-FIR observations in the GOODS-N field. Exploiting two of the 25 SHARDS medium-band filters, F687W17 and F823W17, we select [O II] emission line galaxies at z ~ 0.84 and z ~ 1.23 and characterize their physical properties. Their rest-frame equivalent widths (EWrf([O ii])), line fluxes, luminosities, star formation rates (SFRs), and dust attenuation properties are investigated. The evolution of EW_rf([O II]) closely follows the SFR density evolution of the universe, with a trend of EW_rf([O II]) ∞ (1 + z)^3 up to redshift z ≃1, followed by a possible flattening. The SF properties of the galaxies selected on the basis of their [O II] emission are compared with complementary samples of SFGs selected by their MIR and FIR emission, and also with a general mass-selected sample of galaxies at the same redshifts. We demonstrate observationally that the UVJ diagram (or, similarly, a cut in the specific SFR) is only partially able to distinguish the quiescent galaxies from the SFGs. The SFR–M_* relation is investigated for the different samples, yielding a logarithmic slope ~1, in good agreement with previous results. The dust attenuations derived from different SFR indicators (UV(1600), UV(2800), [O II], IR) are compared and show clear trends with respect to both the stellar mass and total SFR, with more massive and highly star-forming galaxies being affected by stronger dust attenuation.Item The CANDELS/SHARDS multiwavelength catalog in GOODS-N: photometry, photometric redshifts, stellar masses, emission-line fluxes, and star formation rates(Astrophysical journal supplement series, 2019) Pérez González, Pablo Guillermo; Alcalde Pampliega, Belén; Cardiel López, Nicolás; Espino Briones, Néstor; Hernán Caballero, AntonioWe present a WFC3 F160W (H-band) selected catalog in the CANDELS/GOODS-N field containing photometry from the ultraviolet (UV) to the far-infrared (IR), photometric redshifts, and stellar parameters derived from the analysis of the multiwavelength data. The catalog contains 35,445 sources over the 171 arcmin^(2) of the CANDELS F160W mosaic. The 5σ detection limits (within an aperture of radius 0”. 17) of the mosaic range between H = 27.8, 28.2, and 28.7 in the wide, intermediate, and deep regions, which span approximately 50%, 15%, and 35% of the total area. The multiwavelength photometry includes broadband data from the UV (U band from KPNO and LBC), optical (HST/ACS F435W, F606W, F775W, F814W, and F850LP), near-to-mid IR (HST/WFC3 F105W, F125W, F140W, and F160W; Subaru/MOIRCS Ks; CFHT/Megacam K; and Spitzer/IRAC 3.6, 4.5, 5.8, and 8.0 μm), and far-IR (Spitzer/MIPS 24 μm, HERSCHEL/PACS 100 and 160 μm, SPIRE 250, 350 and 500 μm) observations. In addition, the catalog also includes optical medium-band data (R ∼ 50) in 25 consecutive bands, λ = 500–950 nm, from the SHARDS survey and WFC3 IR spectroscopic observations with the G102 and G141 grisms (R ∼ 210 and 130). The use of higher spectral resolution data to estimate photometric redshifts provides very high, and nearly uniform, precision from z = 0–2.5. The comparison to 1485 good-quality spectroscopic redshifts up to z ∼ 3 yields Δz/(1 + z_(spec)) = 0.0032 and an outlier fraction of η = 4.3%. In addition to the multiband photometry, we release value-added catalogs with emission-line fluxes, stellar masses, dust attenuations, UV- and IR-based star formation rates, and rest-frame colors.Item SHARDS: constraints on the dust attenuation law of star-forming galaxies at z∼2(Monthly notices of the Royal Astronomical Society, 2018) Pérez González, Pablo Guillermo; Alcalde Pampliega, Belén; Domínguez Sánchez, Helena; Eliche Moral, María del Carmen; Espino Briones, Néstor; Hernán Caballero, AntonioWe make use of the Survey of High-z Absorption Red and Dead Sources, an ultradeep (<26.5AB) galaxy survey that provides optical photospectra at resolution R similar to 50, via medium-band filters (FWHM similar to 150 angstrom). This data set is combined with ancillary optical and NIR fluxes to constrain the dust attenuation law in the rest-frame NUV region of star-forming galaxies within the redshift window 1.5 < z < 3. We focus on the NUV bump strength (B) and the total-to-selective extinction ratio (R-V), targeting a sample of 1753 galaxies. By comparing the data with a set of population synthesis models coupled to a parametric dust attenuation law, we constrain R-V and B, as well as the colour excess, E(B - V). We find a correlation between R-V and B, which can be interpreted either as a result of the grain size distribution, or a variation of the dust geometry among galaxies. According to the former, small dust grains are associated with a stronger NUV bump. The latter would lead to a range of clumpiness in the distribution of dust within the interstellar medium of star-forming galaxies. The observed wide range of NUV bump strengths can lead to a systematic in the interpretation of the UV slope beta typically used to characterize the dust content. In this study, we quantify these variations, concluding that the effects are Delta beta similar to 0.4.Item SHARDS Frontier Fields: Physical Properties of a Low-mass Lyα Emitter at z=5.75(Astrophysical journal, 2017) Hernán Caballero, Antonio; Pérez González, Pablo Guillermo; Alcalde Pampliega, BelénWe analyze the properties of a multiply imaged Ly alpha (Ly alpha) emitter at z = 5.75 identified through SHARDS Frontier Fields intermediate-band imaging of the Hubble Frontier Fields (HFF) cluster Abell 370. The source, A370-L57, has low intrinsic luminosity (M-UV similar to -16.5), steep UV spectral index (beta = -2.4 +/- 0.1), and extreme rest-frame equivalent width of Ly alpha (EW0 (Ly alpha) = 420(-120)(+180) angstrom). Two different gravitational lens models predict high magnification (mu similar to 10-16) for the two detected counterimages, separated by 7 '', while a predicted third counterimage (mu similar to 3-4) is undetected. We find differences of similar to 50% in magnification between the two lens models, quantifying our current systematic uncertainties. Integral field spectroscopy of A370-L57 with MUSE shows a narrow (FWHM = 204 +/- 10 km s(-1)) and asymmetric Ly alpha profile with an integrated luminosity L(Ly alpha) similar to 10(42) erg s(-1). The morphology in the Hubble Space Telescope bands comprises a compact clump (r(e) < 100 pc) that dominates the Ly alpha and continuum emission and several fainter clumps at projected distances. 1 kpc that coincide with an extension of the Ly alpha emission in the SHARDS F823W17 and MUSE observations. The latter could be part of the same galaxy or an interacting companion. We find no evidence of a contribution from active galactic nuclei to the Ly alpha emission. Fitting of the spectral energy distribution with stellar population models favors a very young (t < 10 Myr), low-mass (M-* 10(6.5) M circle dot), and metal-poor (Z less than or similar to 4 x 10(-3)) stellar population. Its modest star formation rate (SFR similar to 1.0 M circle dot yr(-1)) implies high specific SFR (sSFR similar to 2.5 x 10(-7) yr(-1)) and SFR density (SSFR similar to 7-35 M circle dot yr(-1) kpc(-2)). The properties of A370-L57 make it a good representative of the population of galaxies responsible for cosmic reionization.Item Star-forming galaxies at low-redshift in the SHARDS survey(Astronomy & astrophysics, 2019) Lumbreras Calle, A.; Muñoz Tuñón, C.; Méndez Abreu, J.; Mas Hesse, J.M.; Pérez González, Pablo Guillermo; Alcalde Pampliega, Belén; Arrabal Haro, P.; Cava, A.; Domínguez Sánchez, H.; Eliche Moral, María del Carmen; Alonso Herrera, A.; Borlaff, A.; Gallego Maestro, Jesús; Hernán Caballero, Antonio; Koekemoer, A.M.; Rodríguez Muñoz, L.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 ⟨m3σ⟩~ 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 (AV ~ 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.Item Optically faint massive Balmer break galaxies at z > 3 in the CANDELS/GOODS fields(Astrophysical journal, 2019) Alcalde Pampliega, Belén; Pérez González, Pablo Guillermo; Barro, Guillermo; Domínguez Sánchez, Helena; Eliche Moral, M. Carmen; Cardiel López, Nicolás; Hernán Caballero, Antonio; Rodríguez Muñoz, Lucía; Sánchez Blázquez, Patricia; Esquej, PilarWe present a sample of 33 Balmer break galaxies (BBGs) selected as Hubble Space Telescope/F160W dropouts in the deepest CANDELS/GOODS fields (H >/~ 27.3 mag) but relatively bright in Spitzer/IRAC ([3.6], [4.5] < 24.5 mag), implying red colors (median and quartiles: {H - [3.6]} = 3.1^(3.4)_(2.8) mag ). Half of these BBGs are newly identified sources. Our BBGs are massive ({ log (M/ M_(☉))} = 10.8_(10.4)^( 11.0)), high-redshift ({z} = 4.8_(4.4)^(5.1)), dusty ({A(V)} = 2.0_(1.5)^(2.0) mag) galaxies. The spectral energy distributions (SEDs) of half of our sample indicate that they are star-forming galaxies with typical specific star formation rates (SFRs) of 0.5–1.0 Gyr^(−1), qualifying them as main-sequence (MS) galaxies at 3 < z < 6. One-third of these SEDs indicate the presence of prominent emission lines (Hβ + [O III], Hα + [N II]) boosting the IRAC fluxes and red colors. Approximately 20% of the BBGs are very dusty (A (V) ∼ 2.5 mag) starbursts with strong mid-to-far-infrared detections and extreme SFRs (SFR > 10^(3) M_(☉) yr^(−1)) that place them above the MS. The rest, 30%, are post-starbursts or quiescent galaxies located >2σ below the MS with mass-weighted ages older than 700 Myr. Only two of the 33 galaxies are X-ray-detected active galactic nuclei (AGNs) with optical/near-infrared SEDs dominated by stellar emission, but the presence of obscured AGNs in the rest of the sources cannot be discarded. Our sample accounts for 8% of the total number density of log(M / M_(☉)) > 10 galaxies at z > 3, but it is a significant contributor (30%) to the general population of red log(M / M_(☉) > 11 galaxies at 4 < z < 6. Finally, our results point out that one of every 30 massive log (M / M_(☉) > 11 galaxies in the local universe was assembled in the first 1.5 Gyr after the big bang, a fraction that is not reproduced by state-of-the-art galaxy formation simulations.Item SHARDS Frontier Fields: Physical Properties of a Low-mass Ly alpha Emitter at z=5.75(Astrophysical journal, 2017) Hernán Caballero, Antonio; Pérez González, Pablo Guillermo; Sklias, Panos; Alcalde Pampliega, Belén; otros, ...We analyze the properties of a multiply imaged Ly alpha (Ly alpha) emitter at z = 5.75 identified through SHARDS Frontier Fields intermediate-band imaging of the Hubble Frontier Fields (HFF) cluster Abell 370. The source, A370-L57, has low intrinsic luminosity (M-UV similar to -16.5), steep UV spectral index (beta = -2.4 +/- 0.1), and extreme rest-frame equivalent width of Ly alpha (EW0 (Ly alpha) = 420(-120)(+180) angstrom). Two different gravitational lens models predict high magnification (mu similar to 10-16) for the two detected counterimages, separated by 7 '', while a predicted third counterimage (mu similar to 3-4) is undetected. We find differences of similar to 50% in magnification between the two lens models, quantifying our current systematic uncertainties. Integral field spectroscopy of A370-L57 with MUSE shows a narrow (FWHM = 204 +/- 10 km s(-1)) and asymmetric Ly alpha profile with an integrated luminosity L(Ly alpha) similar to 10(42) erg s(-1). The morphology in the Hubble Space Telescope bands comprises a compact clump (r(e) < 100 pc) that dominates the Ly alpha and continuum emission and several fainter clumps at projected distances. 1 kpc that coincide with an extension of the Ly alpha emission in the SHARDS F823W17 and MUSE observations. The latter could be part of the same galaxy or an interacting companion. We find no evidence of a contribution from active galactic nuclei to the Ly alpha emission. Fitting of the spectral energy distribution with stellar population models favors a very young (t < 10 Myr), low-mass (M-* 10(6.5) M circle dot), and metal-poor (Z less than or similar to 4 x 10(-3)) stellar population. Its modest star formation rate (SFR similar to 1.0 M circle dot yr(-1)) implies high specific SFR (sSFR similar to 2.5 x 10(-7) yr(-1)) and SFR density (SSFR similar to 7-35 M circle dot yr(-1) kpc(-2)). The properties of A370-L57 make it a good representative of the population of galaxies responsible for cosmic reionization.Item Pathways to quiescence: SHARDS view on the star formation histories of massive quiescent galaxies at 1.0 < z < 1.5(Monthly notices of the Royal Astronomical Society, 2016) Domínguez Sánchez, Helena; Pérez González, Pablo Guillermo; Esquej Alonso, María del Pilar; Eliche Moral, María del Carmen; Alcalde Pampliega, Belén; Cardiel López, NicolásWe present star formation histories (SFHs) for a sample of 104 massive (stellar mass M > 10^10 M_⊙) quiescent galaxies (MQGs) at z = 1.0–1.5 from the analysis of spectrophotometric data from the Survey for High-z Absorption Red and Dead Sources (SHARDS) and HST/WFC3 G102 and G141 surveys of the GOODS-North field, jointly with broad-band observations from ultraviolet (UV) to far-infrared (far-IR). The sample is constructed on the basis of rest-frame UVJ colours and specific star formation rates (sSFRs = SFR/Mass). The spectral energy distributions (SEDs) of each galaxy are compared to models assuming a delayed exponentially declining SFH. A Monte Carlo algorithm characterizes the degeneracies, which we are able to break taking advantage of the SHARDS data resolution, by measuring indices such as MgUV and D4000. The population of MQGs shows a duality in their properties. The sample is dominated (85 per cent) by galaxies with young mass-weighted ages, t_M t_M < 2 Gyr, short star formation time-scales, 〈τ〉 ∼ 60–200 Myr, and masses log(M/M_⊙) ∼ 10.5. There is an older population (15 per cent) with t_M t_M = 2–4 Gyr, longer star formation time-scales, 〈τ〉∼ 400 Myr, and larger masses, log(M/M_⊙) ∼ 10.7. The SFHs of our MQGs are consistent with the slope and the location of the main sequence of star-forming galaxies at z > 1.0, when our galaxies were 0.5–1.0 Gyr old. According to these SFHs, all the MQGs experienced a luminous infrared galaxy phase that lasts for ∼500 Myr, and half of them an ultraluminous infrared galaxy phase for ∼100 Myr. We find that the MQG population is almost assembled at z ∼ 1, and continues evolving passively with few additions to the population.