arXiv subjects

Irene Cruz-González

Publications and source records attributed to Irene Cruz-González.

18 recordsLinked to original sources

arXiv2026

SDSS-V Local Volume Mapper (LVM): Dithered Data Cube Reconstruction with 3dcubegen

The Sloan Digital Sky Survey V (SDSS-V) Local Volume Mapper (LVM) is conducting an unprecedented wide-field integral field spectroscopic survey of the Milky Way, the Magellanic Clouds, and nearby galaxies using a strategy based on multiple dithered observations to achieve full spatial coverage, improved spatial sampling, and enhanced spectral depth. However, the scientific exploitation of these observations requires a robust methodology to combine the individual row-stacked spectra (RSS) into homogeneous three-dimensional data cubes. In this work, we present 3DCubeGen, a flexible and scalable reconstruction tool designed to combine multiple LVM dithers while preserving flux and propagating uncertainties. The method enables the coaddition of large datasets, improving the signal-to-noise ratio, enhancing spatial resolution, and increasing sensitivity to faint emission features, following and extending approaches previously implemented in integral field surveys such as CALIFA. We apply 3DCubeGen to a large set of LVM observations, including the Large and Small Magellanic Clouds and nearby galaxies, combining thousands of dithers corresponding to millions of spectra. The resulting data products demonstrate significant improvements in spatial sampling and spectral depth, enabling detailed studies of the ionised gas, stellar populations, and kinematics across extended regions. 3DCubeGen provides a robust and scalable solution for LVM data cube reconstruction and represents a key tool for exploiting the scientific potential of the SDSS-V Local Volume Mapper.

astro-ph.IM↗

arXiv2026

There is no single density: star-forming regions and galaxies hold more dense ionized gas than long assumed

Ionized gas fills star-forming regions and galaxies, and nearly everything we know about its temperature, pressure, mass, and composition is inferred from its emission lines [1-3]. The electron density is needed for all of these, yet a longstanding puzzle has resisted explanation: different density-sensitive lines, applied to the same gas, return values that disagree by up to two orders of magnitude. This is usually attributed either to each line tracing a physically distinct ionization zone or to imperfect atomic data [4-7]. Here we show that the disagreement is neither a flaw in the atomic data nor an ionization-stratification effect, but something more fundamental. Each diagnostic is tuned to a particular density, and when a nebula contains gas across a wide range of densities, as real nebulae do, each line reports the part of that range it is most sensitive to. The diagnostics do not measure a representative average density; they respond to different parts of a broad density distribution. This resolves the discrepancy with a simple relation between the density each line returns and the density it is most sensitive to, a relation that holds from individual H II regions to whole galaxies, near and far, and reveals that ionized nebulae contain far more dense gas than any one diagnostic implies. A nebula has no single electron density to measure, but a broad density distribution, and the masses, pressures, abundances and energetics built on the single-density assumption must be reconsidered, from nearby star-forming regions to galaxies across cosmic time.

astro-ph.GA↗

arXiv2026

The Lockman-SpReSO Project: A Deep X-ray Spectral View of a FIR-selected AGN Population

We present a detailed X-ray spectral analysis of the active galactic nucleus (AGN) population in the Lockman-SpReSO project, a multiwavelength campaign of FIR sources in the Lockman Hole field. Using deep XMM-Newton observations cross-matched with FIR-selected galaxies, we characterize 94 AGNs based on their X-ray spectral properties. The sample is distributed over a large redshift range of $z = 0.07-5$, and reaches a flux limit of $5 \times 10^{-16}\, \mathrm{erg\, s^{-1}\, cm^{-2}}$ in the $0.3-10\, \mathrm{keV}$ band. We model the X-ray spectra using absorbed power-law, reflection, and soft excess components to estimate intrinsic column densities ($N_{\mathrm{H}}$), rest-frame $2-10\, \mathrm{keV}$ luminosities, and iron line equivalent widths $(EW)$. Additionally, we included an advanced model fitting for Compton-thick AGNs (CT-AGNs) using the XCLUMPY model. Our results show an increase in the fraction of obscured AGNs toward higher redshifts, including the identification of one strong and two borderline CT-AGN candidates with $N_{\mathrm{H}} \gtrsim 10^{24}\, \mathrm{cm^{-2}}$. Soft excess emission is detected in 10 AGNs, with an average blackbody temperature of $0.12 \pm 0.02\, \mathrm{keV}$. We also detect the X-ray Baldwin effect in both obscured and unobscured populations, and we found a strong correlation between the torus angular width $(σ_\mathrm{tor})$, dust covering factor $(f_{\mathrm{cov}})$, and X-ray luminosity, described by $f_{\mathrm{cov}} = (-0.1 \pm 0.01) \times \log(L_{2-10\, \mathrm{keV}}/(10^{44}\, \mathrm{erg\, s^{-1}})) + (0.65 \pm 0.01)$, supporting the receding torus scenario. While consistent with deep X-ray surveys, the FIR selection favours the identification of dusty star-forming host galaxies and heavily obscured AGNs.

astro-ph.GA↗

arXiv2025

The Relationship Between Emission Line and Continuum Luminosity and the Baldwin Effect in Blazars. I. The Case of the Mg II λ2798 Å Emission Line

Aims. This study investigates the relationship between the Mg II λ2798 Å emission line and the 3000 Å continuum luminosity, as well as the Baldwin Effect, in a sample of 40,685 radio-quiet (RQ) quasars and 441 Flat Spectrum Radio Quasars (FSRQs). Methods. We perform a comprehensive re-evaluation of the Mg II-3000 Å correlation, explicitly accounting for dispersion introduced by AGN variability. After excluding >3000 radio-loud sources, we employ a binning technique to mitigate variability effects, yielding a refined empirical relation. We also further examine the Non-Thermal Dominance (NTD) parameter, to investigate the dominant source of the continuum. Results. Our analysis reveals statistically significant differences in the slopes of the line-continuum luminosity relation between RQ quasars and FSRQs, with a parallel discrepancy in the Baldwin Effect. These findings imply either (1) intrinsic differences in the accretion disk spectra of RQ AGNs and FSRQs or (2) jet-induced continuum emission in FSRQs contributing to Broad Line Region (BLR) ionization. We also found that a substantial fraction of both RQ quasars (43.8\%) and blazars (55.5\%) exhibit NTD < 1. For blazars, this suggests that the accretion disk alone cannot fully explain BLR ionization; while we interpret NTD < 1 in radio-quiet quasars as a signature of several physical mechanisms: anomalies in the BLR structure (such as outflow or inflows), time lags between continuum and line variations, and the suppression of the UV continuum by a strong corona that diverts accretion power. Finally, we demonstrate that the Baldwin Effect emerges naturally from the line-continuum luminosity relationship, requiring no additional physical mechanism to explain its origin

astro-ph.HE↗

arXiv2025

GLACE survey: OSIRIS/GTC multi-object spectroscopy of the rich galaxy cluster ZwCl 0024.0+1652 at z~0.4. III. The mass-SFR relation and the quenching of cluster galaxies

Galaxy clusters are among the largest and densest structures in the Universe. Their high density generally increases the suppression of star formation, known as quenching, altering galaxy properties. We study the quenching of emission-line galaxies (ELGs) in the rich cluster ZwCl 0024.0+1652 (Cl0024) at redshift $z\sim0.4$, aiming to determine if and how star formation is suppressed. Using multi-object spectroscopy from the GLACE survey, we extracted fluxes and redshifts of [O II]$λ\lambda3727,3729$, $\mathrm{Hβ}$, and [O III]$\lambda5007$ emission lines to derive star formation rates (SFRs) for 173 ELGs. We also performed spectral energy distribution fitting to obtain key evolutionary parameters such as stellar masses ($M_\star$) and the 4000 Å break ($D4000$) index. We derived the $M_\star-\mathrm{SFR}$ relation for 98 star-forming galaxies (SFGs), finding 34.7% exhibit suppressed SFRs in the cluster, compared to 11.0% in the field. While the SFRs show no significant variation with local density, the fraction of SFGs is 1.55 times higher in the cluster outskirts than in intermediate-density regions. The specific SFR decreases strongly with $D4000$ for active SFGs but remains constant for suppressed galaxies. The fraction of suppressed galaxies in the infall region is 2.6 times higher than in the core, especially in the infalling structure B of the cluster. The cluster's total mass does not appear to be a key factor in SFG quenching. Star formation in Cl0024 galaxies is suppressed by the dense cluster environment. This suppression is evident in SFG fractions and parameters tracing long-term evolution, indicating prolonged quenching. The SFGs preferentially reside in low-density regions, while suppressed galaxies dominate the infall region, supporting a 'delayed-then-rapid' quenching scenario.

astro-ph.GA↗

arXiv2024

Dense Molecular gas and Dusty Torus in NGC 4303

Spectrum analysis at 3 mm of the central region ($r\sim$800 pc) of NGC\,4303 showed molecular gas lines of both dense gas tracers (HCN, HNC, HCO$^+$, and C$_2$H) and diffuse gases ($^{13}$CO and C$^{18}$O). Molecular gas derived parameters: $H_2$ mass $M_{H_2}$=(1.75$\pm$0.32)$\times10^{8}$ M$_{\odot}$; radial velocity, V$_{dense}=$178$\pm$60 km\,s$^{-1}$, and V$_{CO}=$151$\pm$29 km\,s$^{-1}$; HCN luminosity $L_{HCN}$=(7.38$\pm$1.40)$\times10^{6}\,\,K\,\,km\,\,s^{-1}\,pc^{2}$; dense gas mass $M_{dense}$=(4.7$\pm$0.3) $\times 10^{7}$ M$_{\odot}$, and dense gas tracers abundances indicating that dense gas contributes significantly to the total molecular gas mass. To explore the AGN nature and central dusty torus of the galaxy, CIGALE was used to fit the integrated spectral energy distribution from submillimeter to UV frequencies. Large torus properties are estimated: luminosity $L_{TORUS}$\,=\,(7.1$\pm$2.8) $\times 10^{43}$ erg s$^{-1}$ and line of sight inclination of 67$\pm$16$^\circ$, which is consistent with a Type 2 AGN; total infrared luminosity $L_{IR}$=(3.51$\,\pm$\,0.30)$\times 10^{44}$ erg s$^{-1}$; star formation rate $SFR$=6.0$\pm$0.3 M$_{\odot}$\,yr$^{-1}$; and found that the AGN contribution is marginal at $\sim$20\%.

astro-ph.GA↗

arXiv2024

The Lockman--SpReSO project. Main properties of infrared selected star-forming galaxies

Methods.We applied distinct selection criteria to attain an SFG sample with minimal AGN contamination. Multiple approaches were used to estimate the intrinsic extinction, SFR and gas-phase metallicity for the SFGs. In conjunction with findings in the literature, we examined the correlation between SFRs and stellar masses ($M_*$), as well as the metallicity evolution depending on $M_*$. Finally, the 3D relationship between $M_*$, SFR and metallicity, is also studied.} Results. From the initial spectroscopic sample of 409 FIR-selected objects from the Lockman--SpReSO catalogue, 69 (17\%) AGNs have been identified and excluded, which is nearly double the percentage found in local studies, leaving a sample of 340 SFGs. The analysis of the $M_*$--SFR relationship revealed that Lockman--SpReSO IR-selected SFGs show signs of evolution at redshifts $z>0.4$, shifting above the main sequence, with a mean value of $\sim0.4$ dex. They are located within the starburst galaxy region since 78\% of the galaxies fall into this category. In addition, no evident flattening was found in the relation to specific SFR with redshift for $\log M_* (M_\odot) \gtrsim 10.5$. In line with the $M_*$--metallicity relation (MZR) outcomes published in previous studies for optically selected SFGs, however, during the analysis of the MZR, it was found that IR-selected SFGs exhibit lower metallicities than those anticipated on the basis of their $M_*$ and redshift. During the investigation of the 3D $M_*$--SFR--metallicity relation (FP), it was established that the research sample is consistent with relations in the existing literature, with an average scatter of $\sim0.2$ dex. However, a re-calibration of the FP when using the SFR obtained from the IR luminosity is required and, in this case, no attenuation in the correlation for $\log M_* (M_\odot) \gtrsim 10.5$ is observed.

astro-ph.GA↗

arXiv2024

GLACE survey: OSIRIS/GTC tuneable imaging of the galaxy cluster ZwCl 0024.0+1652 II. The mass--metallicity relationship and the effect of the environment

In this paper, we revisit the data for the galaxy cluster ZwCl 0024.0+1652 provided by the GLACE survey and study the mass--metallicity function and its relationship with the environment. Here we describe an alternative way to reduce the data from OSIRIS tunable filters. This method gives us better uncertainties in the fluxes of the emission lines and the derived quantities. We present an updated catalogue of cluster galaxies with emission in H$α$ and [N\,{\sc{ii}}] $λλ$6548,6583. We also discuss the biases of these new fluxes and describe the way in which we calculated the mass--metallicity relationship and its uncertainties. We generated a new catalogue of 84 emission-line galaxies with reliable fluxes in [N\,{\sc{ii}}] and H$α$ lines from a list of 174 galaxies. We find a relationship between the clustercentric radius and the density of galaxies. We derived the mass--metallicity relationship for ZwCl 0024.0+1652 and compared it with clusters and field galaxies from the literature. We find a difference in the mass--metallicity relationship when compared to more massive clusters, with the latter showing on average higher values of abundance. This could be an effect of the quenching of the star formation, which seems to be more prevalent in low-mass galaxies in more massive clusters. We find little to no difference between ZwCl 0024.0+1652 galaxies and field galaxies located at the same redshift.

astro-ph.GA↗

arXiv2024

The Lockman-SpReSO project. Galactic flows in a sample of far-infrared galaxies

Methods. We performed measurements of the \MgII, \MgI, \FeIIa, \FeIIb, and \FeIIc\ spectral lines present in the spectra of the selected sample to determine the EW and velocity of the flows observed in the star-forming galaxies. Subsequently, we conducted $10^7$ bootstrap simulations using Spearman's rank correlation coefficient ($ρ_s$) to explore correlations with galaxy properties. Furthermore, we calculated the covering factor, gas density, and optical depth for the measured \ion{Fe}{II} doublets. Results. Our analysis revealed strong correlations between the EW of \ion{Mg}{II} lines and both $M_{*}$ ($ρ_s=0.43$, 4.5$σ$) and SFR ($ρ_s=0.42$, 4.4$σ$). For the \ion{Fe}{II} lines, we observed strong correlations between the EW and SFR ($ρ_s\sim0.65$, $>3.9σ$), with a weaker correlation for $M_{*}$ ($ρ_s\sim0.35$, $>1.9σ$). No notable correlations were found between velocity measurements of \ion{Mg}{II} line and $M_{*}$, SFR, or sSFR of the objects ($ρ_s\sim0.1)$. However, a negative strong correlation was found between the velocity of the \ion{Fe}{II} lines and the SFR of the galaxies ($ρ_s\sim-0.45$, $\sim3σ$). Our results align with previous studies but studying FIR-selected objects. Finally, we detected a candidate \textit{loitering outflow}, a recently discovered subtype of FeLoBAL quasar, at redshift of $z=1.4399$, exhibiting emission in \ion{C}{III}] and low line velocities ($|v|\lesssim$ 200 km/s).

astro-ph.GA↗

arXiv2024

Multi-Epoch Optical Spectroscopy Variability of the Changing-Look AGN Mrk 883

In this work, we present multi-epoch optical spectra of the Seyfert 1.9 galaxy Mrk 883. Data were obtained with the Gran Telescopio Canarias and the \emph{MEGARA} Integral Field Unit mode, archival data from the SDSS-IV MaNGA Survey and the SDSS-I Legacy Survey, and~new spectroscopic observations obtained at San Pedro Mártir Observatory. We report the appearance of the broad component of Hb, emission line, showing a maximum FWHM $\sim$ 5927 $\pm$\, 481\,km\,s$^{-1}$ in the MaNGA spectra, finding evidence for a change from Seyfert 1.9 (23 June 2003) to Seyfert 1.8 (18 May 2018). The~observed changing-look variation from Sy1.9 to Sy1.8 has a timescale $Δ$t\,$\sim$15~y. In~addition, we observe profile and flux broad emission line variability from 2018 to 2023, and a wind component in [OIII]5007~Å, with~a maximum FWHM = 1758 $\pm$ 178 km\,s$^{-1}$, detected on 15 April 2023. In all epochs, variability of the broad lines was found to be disconnected from the optical continuum emission, which shows little or no variations. These results suggest that an ionized-driven wind in the polar direction could be a possible scenario to explain the observed changing-look variations.

astro-ph.GA↗

arXiv2023

3D spectroscopy with GTC-MEGARA of the triple AGN candidate in SDSS J102700.40+174900.8

Triple AGN systems are expected to be the result of the hierarchical model of galaxy formation. Since there are very few of them confirmed as such, we present the results of a new study of the triple-AGN candidate SDSS J102700.40+174900.8 (center nucleus) through observations with $\it{GTC}$-$\it{MEGARA}$ Integral Field Unit. 1D and 2D analysis of the line ratios of the three nuclei allow us to locate them in the EW(H$α$) vs. [Nii] /H$α$ diagram. The central nucleus is found to be a retired galaxy (or fake AGN). The neighbors are found to be a strong AGN (southeastern nucleus, J102700.55+174900.2) compatible with a Sy2 galaxy, and a weak AGN (northern nucleus, J102700.38+174902.6) compatible with a LINER2. We find evidence that the neighbors constitute a dual AGN system (Sy2-LINER2) with a projected separation of 3.98 kpc in the optical bands. The H$α$ velocity map shows that the northern nucleus has an H$α$ emission with a velocity offset of $\sim$-500 km s$^{-1}$, whereas the southeastern nucleus has a rotating disk and H$α$ extended emission at kpc scales. Chandra archival data confirm that the neighbors have X-ray (0.5-2) keV and (2-7) keV emission, whereas the center nucleus shows no X-ray emission. A collisional ring with knots is observed in the HST images of the southeastern nucleus. These knots coincide with star formation regions that along with the ring are predicted in a head-on collision. In this case, the morphology changes are probably due to a minor merger that was produced by the passing of the northern through the southeastern nucleus.

astro-ph.GA↗

arXiv2023

AGN in the CALIFA survey: X-ray detection of nuclear sources

A complete demographic of active galactic nuclei (AGN) is essential to understand the evolution of the Universe. Optical surveys estimate the population of AGN in the local Universe to be of $\sim$ 4%. However, these results could be biased towards bright sources, not affected by the host galaxy attenuation. An alternative method for detecting these objects is through the X-ray emission. In this work, we aim to complement the AGN population of the optical CALIFA survey (941 sources), by using X-ray data from Chandra, which provides the best spatial resolution to date, essential to isolate the nuclear emission from the host galaxy. We study a total of 138 sources with available data. We find 34 new bonafide AGN and 23 AGN candidates, which could increase the AGN population to 7-10\% among the CALIFA survey. X-rays are particularly useful for low-luminosity AGN since they are excluded by the criterion of large equivalent width of the $Hα$ emission line when applied to optical selections. Indeed, placing such a restrictive criteria might cause a loss of up to 70% of AGN sources. X-ray detected sources are preferentially located in the right side of the [$OIII$]/$Hβ$ versus [$NII$]/$Hα$ diagram, suggesting that this diagram might be the most reliable at classifying AGN sources. Our results support the idea that multi-wavelength studies are the best way to obtain a complete AGN population.

astro-ph.GA↗

arXiv2020

The AMUSING++ Nearby Galaxy Compilation: I. Full Sample Characterization and Galactic--Scale Outflows Selection

We present here AMUSING\textrm{++}; the largest compilation of nearby galaxies observed with the MUSE integral field spectrograph so far. This collection consists of 635 galaxies from different MUSE projects covering the redshift interval $0.0002<z<0.1$. The sample and its main properties are characterized and described in here. It includes galaxies of almost all morphological types, with a good coverage in the color-magnitude diagram, within the stellar mass range between 10$^8$ to 10$^{12}$M$_\odot$, and with properties resembling those of a diameter-selected sample. The AMUSING++ sample is therefore suitable to study, with unprecendent detail, the properties of nearby galaxies at global and local scales, providing us with more than 50 million individual spectra. We use this compilation to investigate the presence of galactic outflows. We exploit the use of combined emission-line images to explore the shape of the different ionized components and the distribution along classical diagnostic diagrams to disentangle the different ionizing sources across the optical extension of each galaxy. We use the cross correlation function to estimate the level of symmetry of the emission lines as an indication of the presence of shocks and/or active galactic nuclei. We uncovered a total of 54 outflows, comprising $\sim$8\% of the sample. A large number of the discovered outflows correspond to those driven by active galactic nuclei ($\sim$60\%), suggesting some bias in the selection of our sample. No clear evidence was found that outflow host galaxies are highly star-forming, and outflows appear to be found within all galaxies around the star formation sequence.

astro-ph.GA↗

arXiv2019

An alternative approach to the Finger of God in large scale structures

It is generally accepted that linear theory of growth of structure under gravity produces a squashed structure in the two-point correlation function (2PCF) along the line of sight (LoS). On the other hand, the observed radial spread out structure known as Finger of God (FoG) is attributed to non-linear effects, like virial relaxation or random motions in the inner regions of galaxy clusters, or non-linear terms in collapse theory. In this paper we argue that the squashed structure associated with the redshift-space ($s-$) linear theory 2PCF is obtained only when this function is displayed in real-space ($r-$), or when the mapping from $r-$ to $s-$space is trivialized by one of a series of approximations: the "wide separation" sometimes mistaken by the "distant observer", the $μ(r) \sim μ(s)$ in the cosine of the position vector with the LoS, or plainly by approximating $s \sim r$. To display the $s-$space 2PCF properly in a grid in $s-$space requires one to solve for the mapping function $\bm s(\bm r)$ and its inverse, which exists in the small gravitational disturbance case. We find this mapping by using plane of the sky projections of the $r-$ and $s-$ 2PCFs in the simplest case of the linear Kaiser spectrum with a conservative power-law $r-$space 2PCF. We show that even in this simple case, a structure quite similar to the FoG is observed in the small scale region, while in the large scale the expected squashed structure is obtained. We show that the observed structure is a function of three parameters: the dimensionless growth rate for visible matter ($β$), the power-law exponent ($γ$) and the cosmological distortion given by the Alcock-Paczy{ń}ski parameter ($AP$). We conclude that there appears to be the way of discerning between cosmological and gravitational redshift distortions avoiding known degeneracies.

astro-ph.CO↗

arXiv2012

Characterization of a sample of intermediate-type AGN. II. Host Bulge Properties and Black Hole Mass Estimates

We present a study of the host bulge properties and their relations with the black hole mass on a sample of 10 intermediate-type active galactic nuclei (AGN). Our sample consists mainly of early type spirals, four of them hosting a bar. For 70$^{+10}_{-17}%$ of the galaxies we have been able to determine the type of the bulge, and find that these objects probably harbor a pseudobulge or a combination of classical bulge/ pseudobulge, suggesting that pseudobulges might be frequent in intermediate-type AGN. In our sample, 50\pm14% of the objects show double-peaked emission lines. Therefore, narrow double-peaked emission lines seem to be frequent in galaxies harboring a pseudobulge or a combination of classical bulge/ pseudobulge. Depending on the bulge type, we estimated the black hole mass using the corresponding $M_{BH} - {σ*}$ relation and found them with a range of: 5.69$\pm$0.21 $<$ $\log M_{BH}^{σ*}$ $<$ 8.09$\pm$0.24. Comparing these $M_{BH}^{σ*}$ values with masses derived from the FWHM of H$β$ and the continuum luminosity at 5100 Åfrom their SDSS-DR7 spectra ($M_{BH}$) we find that eight out of ten (80$^{+7}_{-17}$%) galaxies have black hole masses that are compatible within a factor of 3. This result would support that $M_{BH}$ and $M_{BH}^{σ*}$ are the same for intermediate-type AGN as has been found for type 1 AGN. However, when the type of the bulge is taken into account only 3 out of the 7 (43$^{+18}_{-15}%$) objects of the sample have their $M_{BH}^{σ*}$ and $M_{BH}$ compatible within 3-$σ$ errors. We also find that estimations based on the $M_{BH}-σ*$ relation for pseudobulges are not compatible in 50$\pm20%$ of the objects.

astro-ph.CO↗

arXiv2012

Characterization of a sample of intermediate-type AGN. I. Spectroscopic properties and serendipitous discovery of new Dual AGN

A sample of 10 nearby intermediate-type active galactic nuclei (AGN) drawn from the Sloan Digital Sky Survey (SDSS-DR7) is presented. The aim of this work is to provide estimations of the black hole mass for the sample galaxies from the dynamics of the broad line region. For this purpose, a detailed spectroscopic analysis of the objects was done. Using BPT diagnostic diagrams we have carefully classified the objects as true intermediate-type AGN and found that 80%$^{+7.2%}_{-17.3%}$ are composite AGN. The black hole mass estimated for the sample is within 6.54$\pm$0.16\,$<$\,log\,$M_{\rm BH}$\,$<$\,7.81$\pm$0.14. Profile analysis show that five objects (\object{J120655.63+501737.1}, \object{J121607.08+504930.0}, \object{J141238.14+391836.5}, \object{J143031.18+524225.8} and \object{J162952.88+242638.3}) have narrow double-peaked emission lines in both the red (H$α$, [\ion{N}{2}]$λλ$6548,6583 and [\ion{S}{2}]$λλ$6716,6731) and the blue (H$β$ and [\ion{O}{3}]$λλ$4959,5007) region of the spectra, with velocity differences ($ΔV$) between the double peaks within 114\,$<ΔV\,<$\,256 km s$^{-1}$. Two of them, \object{J121607.08+504930.0} and \object{J141238.14+391836.5} are candidates for dual AGN since their double-peaked emission lines are dominated by AGN activity. In searches of dual AGN; Type 1, Type 1I and intermediate-type AGN should be carefully separated, due to the high serendipitous number of narrow double-peaked sources (50%$\pm$14.4%) found in our sample.

astro-ph.CO↗

arXiv2011

Optical Spectroscopic ATLAS of the MOJAVE/2cm AGN Sample (1)

We present an optical spectroscopic atlas at intermediate resolution (8-15A) for 123 core-dominated radio-loud active galactic nuclei with relativistic jets, drawn from the MOJAVE/2cm sample at 15GHz. It is the first time that spectroscopic and photometric parameters for a large sample of such type of AGN are presented. The atlas includes spectral parameters for the emission lines Hb, [O III] 5007, Mg II 2798 and/or C IV 1549 and corresponding data for the continuum, as well as the luminosities and equivalent widths of the Fe II UV/optical. It also contains the homogeneous photometric information in the B-band for 242 sources of the sample, with a distribution peak at BJ=18.0 and a magnitude interval of 11.1< BJ <23.7.

astro-ph.CO↗

arXiv2009

The Synoptic All-Sky Infrared (SASIR) Survey

We are proposing to conduct a multicolor, synoptic infrared (IR) imaging survey of the Northern sky with a new, dedicated 6.5-meter telescope at San Pedro Mártir (SPM) Observatory. This initiative is being developed in partnership with astronomy institutions in Mexico and the University of California. The 4-year, dedicated survey, planned to begin in 2017, will reach more than 100 times deeper than 2MASS. The Synoptic All-Sky Infrared (SASIR) Survey will reveal the missing sample of faint red dwarf stars in the local solar neighborhood, and the unprecedented sensitivity over such a wide field will result in the discovery of thousands of z ~ 7 quasars (and reaching to z > 10), allowing detailed study (in concert with JWST and Giant Segmented Mirror Telescopes) of the timing and the origin(s) of reionization. As a time-domain survey, SASIR will reveal the dynamic infrared universe, opening new phase space for discovery. Synoptic observations of over 10^6 supernovae and variable stars will provide better distance measures than optical studies alone. SASIR also provides significant synergy with other major Astro2010 facilities, improving the overall scientific return of community investments. Compared to optical-only measurements, IR colors vastly improve photometric redshifts to z ~ 4, enhancing dark energy and dark matter surveys based on weak lensing and baryon oscillations. The wide field and ToO capabilities will enable a connection of the gravitational wave and neutrino universe - with events otherwise poorly localized on the sky - to transient electromagnetic phenomena.

astro-ph.IM↗