The fourteenth data release of the Sloan Digital Sky Survey : first spectroscopic data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since 2014 July. This paper describes the second data release from this phase, and the 14th from SDSS overall (making this Data Release Fourteen or DR14). This release makes the data taken by SDSS-IV in its first two years of operation (2014–2016 July) public. Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey; the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data-driven machine-learning algorithm known as “The Cannon”; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from the SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS web site (www.sdss.org) has been updated for this release and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020 and will be followed by SDSS-V

The first 62 AGN observed with SDSS-IV MaNGA - IV: gas excitation and star-formation rate distributions

We present maps of the ionized gas flux distributions, excitation, star-formation rate SFR, surface mass density $\Sigma_{H+}$, and obtain total values of SFR and ionized gas masses {\it M} for 62 Active Galactic Nuclei (AGN) observed with SDSS-IV MaNGA and compare them with those of a control sample of 112 non-active galaxies. The most luminous AGN -- with L(\rm{[OIII]}\lambda 5007) \ge 3.8\times 10^{40}\,\mbox{erg}\,\mbox{s}^{-1}, and those hosted by earlier-type galaxies are dominated by Seyfert excitation within 0.2 effective radius $R_e$ from the nucleus, surrounded by LINER excitation or transition regions, while the less luminous and hosted by later-type galaxies show equally frequent LINER and Seyfert excitation within $0.2\,R_e$. The extent $R$ of the region ionized by the AGN follows the relation $R\propto\,L(\rm{[OIII]})^{0.5}$ -- as in the case of the Broad-Line Region. The SFR distribution over the region ionized by hot stars is similar for AGN and controls, while the integrated SFR -- in the range $10^{-3}-10$\,M$_\odot$\,yr$^{-1}$ is also similar for the late-type sub-sample, but higher in the AGN for 75\% of the early-type sub-sample. We thus conclude that there is no signature of AGN quenching star formation in the body of the galaxy in our sample. We also find that 66\% of the AGN have higher ionized gas masses $M$ than the controls -- in the range 10$^5-3\times10^7$\,M$_\odot$ -- while 75\% of the AGN have higher $\Sigma_{H+}$ within $0.2\,R_e$ than the control galaxies

The 13th Data Release of the Sloan Digital Sky Survey : first spectroscopic data from the SDSS-IV Survey Mapping Nearby Galaxies at Apache Point Observatory

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in 2014 July. It pursues three core programs: the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2), Mapping Nearby Galaxies at APO (MaNGA), and the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). As well as its core program, eBOSS contains two major subprograms: the Time Domain Spectroscopic Survey (TDSS) and the SPectroscopic IDentification of ERosita Sources (SPIDERS). This paper describes the first data release from SDSS-IV, Data Release 13 (DR13). DR13 makes publicly available the first 1390 spatially resolved integral field unit observations of nearby galaxies from MaNGA. It includes new observations from eBOSS, completing the Sloan Extended QUasar, Emission-line galaxy, Luminous red galaxy Survey (SEQUELS), which also targeted variability-selected objects and X-ray-selected objects. DR13 includes new reductions of the SDSS-III BOSS data, improving the spectrophotometric calibration and redshift classification, and new reductions of the SDSS-III APOGEE-1 data, improving stellar parameters for dwarf stars and cooler stars. DR13 provides more robust and precise photometric calibrations. Value-added target catalogs relevant for eBOSS, TDSS, and SPIDERS and an updated red-clump catalog for APOGEE are also available. This paper describes the location and format of the data and provides references to important technical papers. The SDSS web site, http://www.sdss.org, provides links to the data, tutorials, examples of data access, and extensive documentation of the reduction and analysis procedures. DR13 is the first of a scheduled set that will contain new data and analyses from the planned ∼6 yr operations of SDSS-IV

The Eddington ratio-dependent ‘changing look’ events in NGC 2992

We present an analysis of historical multiwavelength emission of the `Changing Look’ (CL) Active Galactic Nucleu (AGN) in NGC 2992, covering epochs ranging from 1978 to 2021, as well as new X-ray and optical spectra. The galaxy presents multiple Seyfert type transitions from Type 2 to intermediate-type, losing and regaining its Hα broad emission lines (BEL) recurrently. In X-rays, the source shows intrinsic variability with the absorption corrected luminosity varying by a factor of ∼ 40. We rule-out tidal disruption events or variable obscuration as causes of the type transitions, and show that the presence and the flux of th Hα BEL is directly correlated with the 2–10 keV X-ray luminosity (L2−10): the component disappears at L2−10 ≤ 2.6 × 1042 erg cm−2 s−1; this luminosity value translates into an Eddington ratio (λEdd) of ∼ 1 per cent. The λEdd in which the BEL transitions occur is the same as the critical value at which a state transition between a radiatively inefficient accretion flow and a thin accretion disk is expected, such similarity suggests that the AGN is operating at the threshold mass accretion rate between the two accretion modes. We find a correlation between the narrow Fe Kα flux and λEdd, and an anticorrelation between full-width at half maximum of Hα BEL and λEdd, in agreement with theoretical predictions. Two possible scenarios for type transitions are compatible with our results: either the dimming of the AGN continuum, which reduces the supply of ionizing photons available to excite the gas in the Broad Line Region (BLR), or the fading of the BLR structure itself occurs as the low accretion rate is not able to sustain the required cloud flow rate in a disc-wind BLR model

Active galactic nuclei signatures in Red Geyser galaxies from Gemini GMOS-IFU observations

Red Geysers are quiescent galaxies with galactic scale ionized outflows, likely due to low-luminosity active galactic nuclei (AGN). We used Gemini GMOS-IFU observations of the inner~1–3 kpc of nine Red Geysers selected from the MaNGA survey to study the gas ionization and kinematics. The emission-line ratios suggest the presence of Seyfert/LINER (Low Ionization Nuclear Emission Region) nuclei in all sources. Two galaxies show Hα equivalent width ( Hα EW) larger than 3 Å (indicative of AGN ionization) within an aperture 2 . 5 of diameter (1.3–3.7 kpc at the distance of galaxies) for MaNGA data, while with the higher resolution GMOS data, four galaxies present Hα EW>3 Å within an aperture equal to the angular resolution (0.3–0.9 kpc). For two objects with GMOS-IFU data, the Hα EW is lower than 3 Å but larger than 1.5 Å, most probably due to a faint AGN. The spatially resolved electron density maps show values between 100 and 3000 cm −3 and are consistent with those determined in other studies. The large (MaNGA) and the nuclear scale (GMOS-IFU) gas velocity fields are misaligned, with a kinematic position angle difference between 12◦ and 60◦. The [N II] λ6583 emission-line profiles are asymmetrical, with blue wings on the redshifted side of the velocity field and red wings on the blueshifted side. Our results support previous indications that the gas in Red Geysers is ionized by an AGN, at least in their central region, with the presence of outflows, likely originating in a precessing accretion disc

The first 62 AGN observed with SDSS-IV MaNGA – IV. Gas excitation and star formation rate distributions

We present maps of the ionized gas flux distributions, excitation, star formation rate (SFR), surface mass density ΣH+, and obtain total values of SFR and ionized gas masses M for 62 active galactic nuclei (AGN) observed with SDSS-IV MaNGA and compare them with those of a control sample of 112 non-active galaxies. The most luminous AGN – with L([OIII]λ5007)≥3.8×1040ergs−1, and those hosted by earlier type galaxies are dominated by Seyfert excitation within 0.2 effective radius Re from the nucleus, surrounded by LINER excitation or transition regions, while the less luminous and hosted by later-type galaxies show equally frequent LINER and Seyfert excitation within 0.2Re. The extent R of the region ionized by the AGN follows the relation R∝L([OIII])0.5 – as in the case of the broad-line region. The SFR distribution over the region ionized by hot stars is similar for AGN and controls, while the integrated SFR – in the range 10−3–10 M⊙ yr−1 is also similar for the late-type subsample, but higher in the AGN for 75 per cent of the early-type subsample. We thus conclude that there is no signature of AGN quenching star formation in the body of the galaxy in our sample. We also find that 66 per cent of the AGN have higher ionized gas masses M than the controls – in the range 105–3 × 107 M⊙ – while 75 per cent of the AGN have higher ΣH+ within 0.2Re than the control galaxie

Precessing winds from the nucleus of the prototype Red Geyser?

Supermassive black holes (SMBHs) are present at the centre of most galaxies, with the related mass accretion processes giving origin to outflows in active galactic nuclei (AGNs). It has been presumed that only intense winds from luminous AGNs were able to suppress star formation until the discovery of a new class of galaxies with no recent star formation and with the nucleus in a quiescent state showing kpc scale outflows. We used SDSS MaNGA and Gemini Integral Field Spectroscopy of the prototype Red Geyser Akira and found that the orientation of the outflow changes by about 50° from its nucleus to kpc scales. A possible interpretation is that the outflow is produced by a precessing accretion disc due to a misalignment between the orientation of the disc and the spin of the SMBH. The precession of the central source is also supported by a similar change in the orientation of the ionization pattern. Although similar behaviour has commonly being reported for collimated relativistic jets, the precession of an AGN wide wind is reported here for the first time, implying on a larger work surface of the wind, which in turn increases the star formation suppression efficiency of the outflow

The first 62 AGN observed with SDSS-IV MaNGA – III : stellar and gas kinematics

We investigate the effects of active galactic nuclei (AGN) on the gas kinematics of their host galaxies, using MaNGA data for a sample of 62 AGN hosts and 109 control galaxies (inactive galaxies). We compare orientation of the line of nodes (kinematic position angle – PA) measured from the gas and stellar velocity fields for the two samples. We found that AGN hosts and control galaxies display similar kinematic PA offsets between gas and stars. However, we note that AGN have larger fractional velocity dispersion σ differences between gas and stars [σfrac = (σgas − σstars)/σstars] when compared to their controls, as obtained from the velocity dispersion values of the central (nuclear) pixel (2. 5 diameter). The AGN have a median value of σfrac of AGN = 0.04, while the median value for the control galaxies is CTR =−0.23. 75 per cent of the AGN show σfrac > −0.13, while 75 per cent of the normal galaxies show σfrac < −0.04, thus we suggest that the parameter σfrac can be used as an indicator of AGN activity. We find a correlation between the [OIII]λ5007 luminosity and σfrac for our sample. Our main conclusion is that the AGN already observed with MaNGA are not powerful enough to produce important outflows at galactic scales, but at 1–2 kpc scales, AGN feedback signatures are always present on their host galaxies

The first 62 AGNs observed with SDSS-IV MaNGA : I. Their characterization and definition of a control sample

We report the characterization of the first 62 Mapping Nearby Galaxies at the Apache Point Observatory active galactic nuclei (AGNs) hosts and the definition of a control sample of non-active galaxies. This control sample was selected in order to match the AGN hosts in terms of stellar mass, redshift, visual morphology and inclination. The stellar masses are in the range 9.4 < log M/M < 11.5, and most objects have redshifts ≤0.08. The AGN sample is mostly comprised low-luminosity AGN, with only 17 ‘strong AGN’ with L([O III]λ5007 Å) ≥ 3.8 × 1040 erg s−1. The inner 1–3 kpc of the control sample galaxies are dominated by the oldest (≥ 4Gyr) component, with a small contribution of intermediate age and young stars (<940 Myr). Examining the relationship between the stellar population properties and L([O III]), we find that with increasing L([O III]), the AGN exhibit a decreasing contribution from the oldest stellar population relative to control galaxies and an increasing contribution from the younger components (∼40 Myr).We also find a correlation of the mean age differences (AGN–control) with L([O III]), in the sense that more luminous AGNs are younger than the control objects, while the low-luminosity AGNs are older. These results support a connection between the growth of the galaxy bulge via formation of new stars and the growth of the Supermassive Black Hole via accretion in the AGN phase

Perfis de duplo-pico : revelando a presença de discos de acreção na região de linhas largas de galáxias ativas

A energia emitida pelos núcleos ativos de galáxias (AGN’s) ´e provida através do escoamento acretivo de matéria em direção ao buraco negro super massivo central (SMBH). Tal escoamento se da sob a forma de um disco de acreção. As principais evidências observacionais da presença do disco são: (i) sua emissão térmica nos AGN’s mais luminosos, que d´a origem ao chamado big blue bump observado na região espectral do ultravioleta e (ii) a emissão de linhas largas com duplo-pico, entendidas como provenientes da recombinação do Hidrogênio nas regiões mais externas do disco de acreção. Os AGN’s menos luminosos, LLAGN’s, não apresentam o big blue bump, o que sugere que o disco de acreção tem uma natureza diferente; sua distribuição espectral de energia tem sido modelada através de um disco que é espesso na região interna, num regime de acreção de gás “radiativamente ineficiente”(RIAF), que é responsável pela emissão de fótons de mais alta energia (raios-X). Neste trabalho, apresentamos o monitoramento espectral de 2 LLAGN’s que apresentam linhas de emissão largas de Hα (FWHM _10.000 km/s) com duplo-pico: NGC1097 e NGC7213. Acredita-se que estas linhas sejam emitidas pelo g´as que se encontra na parte mais externa do disco de acreção, que ´e ionizado pelos raios-X emitidos pelo RIAF central. No caso de NGC1097, monitoramos o AGN em raios-X e UV – usando o satélite Swift, e também o perfil em duplo-pico – usando o telescópio SOAR entre agosto de 2012 e fevereiro de 2013. Este monitoramento permitiu que estudássemos a amplitude variacional de cada uma das curvas de luz obtidas e também aplicássemos a técnica de correlação cruzada entre as curvas de luz de raio-X e do ótico com o objetivo de elucidar se as variações no perfil em duplo-pico são reverberações das variações do contínuo ionizante de alta energia. Através deste monitoramento conseguimos colocar vínculos do limite superior para a escala de variabilidade mais curta do perfil, _ 5 dias, assim como através da modelagem dos perfis colocar vínculos na estrutura da região emissora. No caso de NGC7213 monitoramos o perfil em duplopico do AGN entre setembro de 2011 e julho de 2013. Observamos variabilidades do perfil em duas escalas de tempo: (1) a mais curta, entre 7 e 28 dias, associada as variações do fluxo total integrado do perfil e outra (2) mais longa & 3 meses, nas variações da intensidade relativa dos fluxos dos lados azul e vermelho do perfil e associada a escala de tempo dinâmica do disco de acreção. Modelamos a emissão em duplo-pico deste objeto como originária de um disco de acreção Kepleriano e relativístico, cujas características de variabilidade observadas podem ser explicadas através da rotação de um braço espiral no disco cuja emissão ´e maior do que a do disco subjacente. Por fim, estendemos a modelagem dos perfis de emissão largos de Hα para as galáxias Seyfet 1 do Palomar Sky Survey of Nearby Galaxies que apresentam emissão em duplo-pico: NGC3516, NGC4151, NGC4235, NGC5273, NGC5548. Concluímos que os perfis de emissão largos nesses objetos mais luminosos requerem uma modelagem com duas componentes: (1) uma muito larga e de duplo-pico que ´e originária da emissão do gás no disco de acreção; (2) e outra componente Gaussian de mais baixa velocidade para reproduzir a parte mais central do perfil, associada ao gás localizado além do disco. Identificamos que a componente disco é dominante em relação a emissão e que o angulo de inclinação do disco é o parâmetro mais importante na modelagem do perfil desses objetos. A geometria tipo disco tem implicações para a determinação da massa do buraco negro em galáxias ativas através do produto virial e identificando a relação entre o fator f e a largura da linha propomos um aprimoramento na obtenção de M• em galáxias ativas.The energy emitted by active galactic nuclei (AGN) is powered via accretion flows onto the central supermassive black hole (SMBH), usually in the form of an “accretion disk”in which the gas slowly spirals towards the SMBH. The most clear spectral signatures of accretion disks are: (i) their thermal emission in the most luminous AGN, which originates the so called big blue bump observed in the ultravaviolet and (ii) the emission of broad double-peaked lines, which are thought to originate via recombination of H and He atoms in the outer parts of the accretion disk. The low luminosity AGN’s (LLAGN), usually do not show the big blue bump, suggesting that their accretion flows are distinct; indeed, their spectral energy distribution have been modeled by an accretion disk in which the innermost part is geometrically thick, accreting in a radiativelly inefficient regime (RIAF) that emits high energy fotons (X-rays). In this work, we present the spectral monitoring of 2 LLAGN – NGC1097 and NGC7213 – that show broad (10,000 kms−1) double-peaked Hα emission lines, thought to be emitted by the gas in the outer parts of the accretion disk, which is ionized by the Xrays emitted by the central RIAF. In the case of NGC1097, we monitored the AGN in X-rays and UV – using the Swift satellite, and also the double-peaked profile – using the SOAR telescope between 2012 August and 2013 February. This monitoring allowed us to study the variability amplitude of each light curve as well as to apply the cross correlation technique to the light curves in X-rays and optical in order to investigate if the variations in the double-peaked profile are a reverberation of the variations in X-rays and UV (ionizing radiation). The monitoring allowed us to put constraints on the minimum variability timescale and on the structure of the line-emiting region. In the case of NGC7213 we monitired the broad double-peaked profile between 2011 September and 2013 July. We detected variabiliy of the profile in two timescales: (1) the shortest, beween 7 and 28 days, associated with vatiations in the integrated flux of the double-peaked line and another (2) larger, & 3 months, associated with variations in the relative intensity of the fluxes of the blue and red sides of the profile and identified with the dynamical timescale of the accretion disk. We modeled the double-peaked emission of this object as due the gas emission in a Keplerian and relativistic accretion disk, whose the variability features can be explained via rotation of a spiral arm in the disk which is brigther than the underlying disk. Finally, we extended the study of the modeling of broad Hα profiles to Seyfet 1 galaxies that display double-peaked profiles in the Palomar Sky Surver of Nearby Galaxies, namely NGC3516, NGC4151, NGC4235, NGC5273, NGC5548. We concluded that the broad Hα emission profiles of these galaxies require a two component modeling: (1) a very broad and double-peaked component originating from the gas in the accretion disk and another (2) low-velocity Gaussian component required to reproduce the center of the profile, associated with gas at lower velocities probably beyond the disk. We concluded that the disk component dominates at highest velocities and the inclination is the most important parameter in the determination of the width of the double-peaked profiles. The disk-like geometry has implications for the determination of the mass of the central SMBH in AGN via the virial product M• = and by identifying a relation between the factor f and the width of the broad line we propose an improvement in the estimate of the SMBH masses in Type 1 AGN