Extreme Emission Line Galaxies (EELGs) stand as remarkable objects due to their extremely metal poor environment and intense star formation. Considered as local analogues of high-redshift galaxies in ...the peak of their star-forming activity, they offer insights into conditions prevalent during the early Universe. Assessment of their stellar and gas properties is, therefore, of critical importance, which requires the assembly of a considerable sample, comprehending a broad redshift range. The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (JPAS) plays a significant role in assembling such a sample, encompassing approximately 8000 deg2 and employing 54 narrow-band optical filters. The present work describes the development and subsequent application of the tools that will be employed in the forthcoming JPAS spectrophotometric data, allowing for the massive and automated characterization of EELGs that are expected to be identified. This fully automated pipeline (requiring only the object coordinates from users) constructs Spectral Energy Distributions (SEDs) by retrieving virtually all the available multi-wavelength photometric data archives, employs SED fitting tools and identifies optical emission lines. It was applied to the sample of extreme line emitters identified in the miniJPAS Survey, and its derived physical properties such as stellar mass and age, coupled with fundamental relations, mirror results obtained through spectral modeling of SDSS spectra. Thorough testing using galaxies with documented photometric measurements across different wavelengths confirmed the pipeline's accuracy, demonstrating its capability for automated analysis of sources with varying characteristics, spanning brightness, morphology, and redshifts. The modular nature of this pipeline facilitates any addition from the user.
We use type Ia supernovae (SNe Ia) data obtained by the Sloan Digital Sky Survey-II Supernova Survey (SDSS-II/SNe) in combination with the publicly available SDSS DR16 fiber spectroscopy of their ...host galaxies to correlate SNe Ia light-curve parameters and Hubble residuals to several host galaxy properties. Fixed-aperture fiber spectroscopy suffers from aperture effects: the fraction of the galaxy covered by the fiber varies depending on its projected size on the sky, thus measured properties are not representative of the whole galaxy. The advent of Integral Field Spectroscopy has provided a way for correcting the missing light, by studying how these galaxy parameters change with the aperture size. Here we study how the standard SN host galaxy relations change once global host galaxy parameters are corrected for aperture effects. We recover previous trends on SN Hubble residuals with host galaxy properties, but we find that discarding objects with poor fiber coverage instead of correcting for aperture loss introduces biases in the sample that affect SN host galaxy relations. The net effect of applying the commonly used \(g\)-band fraction criterion is discarding intrinsically faint \mbox{SNe~Ia} in high-mass galaxies, thus artificially increasing the height of the mass step by 0.02 mag and its significance. Current and next generation of fixed-aperture fiber spectroscopy surveys, such as DES, DESI or TiDES in 4MOST, that aim at study SN and galaxy correlations must consider, and correct for, these effects.
This paper presents the first results of an H{alpha} imaging survey of galaxies in the central regions of the A2151 cluster. A total of 50 sources were detected in H{alpha}, from which 41 were ...classified as secure members of the cluster and 2 as likely members based on spectroscopic and photometric redshift considerations. The remaining seven galaxies were classified as background contaminants and thus excluded from our study on the H{alpha} properties of the cluster. The morphologies of the 43 H{alpha} selected galaxies range from grand design spirals and interacting galaxies to blue compacts and tidal dwarfs or isolated extragalactic H II regions, spanning a range of magnitudes of -21 {<=} M{sub B} {<=} -12.5 mag. From these 43 galaxies, 7 have been classified as active galactic nucleus (AGN) candidates. These AGN candidates follow the L(H{alpha}) versus M{sub B} relationship of the normal galaxies, implying that the emission associated with the nuclear engine has a rather secondary impact on the total H{alpha} emission of these galaxies. A comparison with the clusters Coma and A1367 and a sample of field galaxies has shown the presence of cluster galaxies with L(H{alpha}) lower than expected for their M{sub B} , a consequence of the cluster environment. This fact results in differences in the L(H{alpha}) versus EW(H{alpha}) and L(H{alpha}) distributions of the clusters with respect to the field, and in cluster-to-cluster variations of these quantities, which we propose are driven by a global cluster property as the total mass. In addition, the cluster H{alpha} emitting galaxies tend to avoid the central regions of the clusters, again with different intensity depending on the cluster total mass. For the particular case of A2151, we find that most H{alpha} emitting galaxies are located close to the regions with the higher galaxy density, offset from the main X-ray peak. Overall, we conclude that both the global cluster environment and the cluster merging history play a non-negligible role in the integral star formation properties of clusters of galaxies.
This paper presents the first results of an Halpha imaging survey of galaxies in the central regions of the A2151 cluster. A total of 50 sources were detected in Halpha, from which 41 were classified ...as secure members of the cluster and 2 as likely members based on spectroscopic and photometric redshift considerations. The remaining seven galaxies were classified as background contaminants and thus excluded from our study on the Halpha properties of the cluster. The morphologies of the 43 Halpha selected galaxies range from grand design spirals and interacting galaxies to blue compacts and tidal dwarfs or isolated extragalactic H II regions, spanning a range of magnitudes of -21 < = MB < = -12.5 mag. From these 43 galaxies, 7 have been classified as active galactic nucleus (AGN) candidates. These AGN candidates follow the L(Halpha) versus MB relationship of the normal galaxies, implying that the emission associated with the nuclear engine has a rather secondary impact on the total Halpha emission of these galaxies. A comparison with the clusters Coma and A1367 and a sample of field galaxies has shown the presence of cluster galaxies with L(Halpha) lower than expected for their MB, a consequence of the cluster environment. This fact results in differences in the L(Halpha) versus EW(Halpha) and L(Halpha) distributions of the clusters with respect to the field, and in cluster-to-cluster variations of these quantities, which we propose are driven by a global cluster property as the total mass. In addition, the cluster Halpha emitting galaxies tend to avoid the central regions of the clusters, again with different intensity depending on the cluster total mass. For the particular case of A2151, we find that most Halpha emitting galaxies are located close to the regions with the higher galaxy density, offset from the main X-ray peak. Overall, we conclude that both the global cluster environment and the cluster merging history play a non-negligible role in the integral star formation properties of clusters of galaxies.
This paper presents the first results of an H Delta *a imaging survey of galaxies in the central regions of the A2151 cluster. A total of 50 sources were detected in H Delta *a, from which 41 were ...classified as secure members of the cluster and 2 as likely members based on spectroscopic and photometric redshift considerations. The remaining seven galaxies were classified as background contaminants and thus excluded from our study on the H Delta *a properties of the cluster. The morphologies of the 43 H Delta *a selected galaxies range from grand design spirals and interacting galaxies to blue compacts and tidal dwarfs or isolated extragalactic H II regions, spanning a range of magnitudes of -21 <= MB <= -12.5 mag. From these 43 galaxies, 7 have been classified as active galactic nucleus (AGN) candidates. These AGN candidates follow the L(H Delta *a) versus MB relationship of the normal galaxies, implying that the emission associated with the nuclear engine has a rather secondary impact on the total H Delta *a emission of these galaxies. A comparison with the clusters Coma and A1367 and a sample of field galaxies has shown the presence of cluster galaxies with L(H Delta *a) lower than expected for their MB, a consequence of the cluster environment. This fact results in differences in the L(H Delta *a) versus EW(H Delta *a) and L(H Delta *a) distributions of the clusters with respect to the field, and in cluster-to-cluster variations of these quantities, which we propose are driven by a global cluster property as the total mass. In addition, the cluster H Delta *a emitting galaxies tend to avoid the central regions of the clusters, again with different intensity depending on the cluster total mass. For the particular case of A2151, we find that most H Delta *a emitting galaxies are located close to the regions with the higher galaxy density, offset from the main X-ray peak. Overall, we conclude that both the global cluster environment and the cluster merging history play a non-negligible role in the integral star formation properties of clusters of galaxies.
21 cm H I line observations were made with the Arecibo Gregorian telescope of 9 H I clouds in the Hercules Cluster which were reported as tentative detections in a VLA H I study of the cluster ...(Dickey \cite{Dickey97}) and for which our deep CCD imaging failed to find any optical counterparts. No sensitive observations could be made of one of these (sw-174) due to the presence of a close-by strong continuum source. The other 8 tentative H I detections were not confirmed by the Arecibo H I measurements. The CCD images did reveal faint, low surface brightness counterparts near the centres of two other VLA H I sources invisible on the Palomar Sky Survey, sw-103 and sw-194.
We study two galaxy samples selected in ultraviolet (UV) and in far-infrared (FIR) for which the spectral energy distributions (SEDs) from the far UV (FUV) to the FIR are available. We compare the ...observed SEDs to modelled SEDs with several star formation histories (SFHs; decaying star formation rate plus burst) and attenuation laws (power law + 2175 Angstroem bump). The Bayesian method allows to estimate statistically the best parameters by comparing each observed SED to the full set of 82800 models. We reach the conclusion that the UV dust attenuation cannot be estimated correctly from an SED analysis if the FIR information is not used. The deduced dispersion is larger than with the FIR data and the distribution is not symetrically distributed about zero: there is an over-estimation for UV-selected galaxies and an under-estimation for FIR-selected galaxies. The output from the analysis process suggests that UV-selected galaxies have attenuation laws in average similar to the LMC extinction while FIR-selected galaxy attenuation laws more resemble the MW extinction law. The dispersion about the average relation in the Log(Fdust/Ffuv) vs. FUV-NUV diagram (once the main relation with FUV-NUV is accounted for) is explained by two other parameters: the slope of the attenuation law and the instantaneous birthrate parameter b_0 for UV-selected galaxies and the same ones plus the strength of the bump for the FIR-selected galaxies. We propose a recipe to estimate the UV dust attenuation for UV-galaxies only (that should be used whenever the FIR information is not available because the resulting Afuv is poorly defined with an uncertainty of about 0.32): A_{FUV} = 1.4168 (FUV-NUV)^2 + 0.3298 (NUV-I)^2 + 2.1207 (FUV-NUV) + 2.7465 (NUV-I) + 5.8408
We report on preliminary results from an ongoing study of star-forming galaxies in the Virgo Cluster with the aim of understanding the role played by the environment on their evolution. First, the ...chemical evolution of nine spiral galaxies located in the inner parts of the cluster has been studied using chemical abundances recomputed for a sample of HII regions. Second, long-slit optical spectroscopy has been obtained for 22 blue dwarf galaxies selected across the Virgo central field. This sample is a subset of a larger list of dwarf galaxies for which deep Hα imaging has been collected. Chemical abundances have been derived for the sample using either a direct estimation of the electron temperature or empirical calibrations. Abundance results correlate with blue and near infrared magnitude, total HI mass and color.PUBLICATION ABSTRACT
Disky bulges in spiral galaxies are commonly thought to form out of disk materials (mainly) via bar driven secular processes, they are structurally and dynamically distinct from `classical bulges' ...built in violent merger events. We use high-resolution GTC/MEGARA integral-field unit spectroscopic observations of the Sa galaxy NGC 7025, obtained during the MEGARA commissioning run, together with detailed 1D and 2D decompositions of this galaxy's SDSS \(i\)-band data to investigate the formation of its disky (bulge) component which makes up \(\sim 30\%\) of the total galaxy light. With a Sérsic index \(n \sim 1.80 \pm 0.24\), half-light radius \(R_{\rm e} \sim 1.70 \pm 0.43\) kpc and stellar mass \(M_{*} \sim (4.34 \pm 1.70) \times10^{10} M_{\odot}\), this bulge dominates the galaxy light distribution in the inner \(R \sim 15"\) (\(\sim 4.7\) kpc). Measuring the spins (\(\lambda\)) and ellipticities (\(\epsilon\)) enclosed within nine different circular apertures with radii \(R \le R_{\rm e}\), we show that the bulge, which exhibits a spin track of an outwardly rising \(\lambda\) and \(\epsilon\), is a fast rotator for all the apertures considered. Our findings suggest that this inner disky component is a pseudo-bulge, consistent with the stellar and dust spiral patterns seen in the galaxy down to the innermost regions but in contrast to the classical bulge interpretation favored in the past. We propose that a secular process involving the tightly wound stellar spiral arms of NGC 7025 may drive gas and stars out of the disk into the inner regions of the galaxy, building up the massive pseudo-bulge.
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