20 research outputs found
SDSS-IV eBOSS Spectroscopy of X-ray and WISE AGN in Stripe 82X: Overview of the Demographics of X-ray and Mid-Infrared Selected Active Galactic Nuclei
We report the results of a Sloan Digital Sky Survey-IV eBOSS program to
target X-ray sources and mid-infrared-selected WISE AGN candidates in a 36.8
deg region of Stripe 82. About half this survey (15.6 deg) covers the
largest contiguous portion of the Stripe 82 X-ray survey. This program
represents the largest spectroscopic survey of AGN candidates selected solely
by their WISE colors. We combine this sample with X-ray and WISE AGN in the
field identified via other sources of spectroscopy, producing a catalog of 4847
sources that is 82% complete to . Based on X-ray luminosities or WISE
colors, 4730 of these sources are AGN, with a median sample redshift of
. About 30% of the AGN are optically obscured (i.e., lack broad lines
in their optical spectra). BPT analysis, however, indicates that 50% of the
WISE AGN at have emission line ratios consistent with star-forming
galaxies, so whether they are buried AGN or star-forming galaxy contaminants is
currently unclear. We find that 61% of X-ray AGN are not selected as MIR AGN,
with 22% of X-ray AGN undetected by WISE. Most of these latter AGN have high
X-ray luminosities ( erg s), indicating that MIR
selection misses a sizable fraction of the highest luminosity AGN, as well as
lower luminosity sources where AGN heated dust is not dominating the MIR
emission. Conversely, 58% of WISE AGN are undetected by X-rays, though we
do not find that they are preferentially redder than the X-ray detected WISE
AGN.Comment: resubmitted to AAS Journals after addressing referee's comments. 21
pages, 17 figures, 5 Tables. Tables 4 & 5 summarize the demographics of the
sample. Figures 15 & 16 compare AGN populations from X-ray and MIR selection.
The catalog (in fits format) can be downloaded at
http://doi.org/10.5281/zenodo.257735
The Discovery of the First "Changing Look" Quasar: New Insights into the Physics & Phenomenology of AGN
SDSS J015957.64+003310.5 is an X-ray selected, AGN from the Stripe
82X survey that transitioned from a Type 1 quasar to a Type 1.9 AGN between
2000 and 2010. This is the most distant AGN, and first quasar, yet observed to
have undergone such a dramatic change. We re-observed the source with the
double spectrograph on the Palomar 5m telescope in July 2014 and found that the
spectrum is unchanged since 2010. From fitting the optical spectra, we find
that the AGN flux dropped by a factor of 6 between 2000 and 2010 while the
broad H emission faded and broadened. Serendipitous X-ray observations
caught the source in both the bright and dim state, showing a similar 2-10 keV
flux diminution as the optical while lacking signatures of obscuration. The
optical and X-ray changes coincide with -band magnitude variations over
multiple epochs of Stripe 82 observations. We demonstrate that variable
absorption, as might be expected from the simplest AGN unification paradigm,
does not explain the observed photometric or spectral properties. We interpret
the changing state of J0159+0033 to be caused by dimming of the AGN continuum,
reducing the supply of ionizing photons available to excite gas in the
immediate vicinity around the black hole. J0159+0033 provides insight into the
intermittency of black hole growth in quasars, as well as an unprecedented
opportunity to study quasar physics (in the bright state) and the host galaxy
(in the dim state), which has been impossible to do in a single sources until
now.Comment: accepted for publication in Ap
BAT AGN spectroscopic survey - XV: the high frequency radio cores of ultra-hard X-ray selected AGN
We have conducted 22 GHz radio imaging at 1 arcsec resolution of 100 low-redshift AGN selected at 14–195 keV by the Swift-BAT. We find a radio core detection fraction of 96 per cent, much higher than lower frequency radio surveys. Of the 96 radio-detected AGN, 55 have compact morphologies, 30 have morphologies consistent with nuclear star formation, and 11 have sub-kpc to kpc-scale jets. We find that the total radio power does not distinguish between nuclear star formation and jets as the origin of the radio emission. For 87 objects, we use optical spectroscopy to test whether AGN physical parameters are distinct between radio morphological types. We find that X-ray luminosities tend to be higher if the 22 GHz morphology is jet-like, but find no significant difference in other physical parameters. We find that the relationship between the X-ray and core radio luminosities is consistent with the L_R/L_X ∼ 10⁻⁵ of coronally active stars. We further find that the canonical fundamental planes of black hole activity systematically overpredict our radio luminosities, particularly for objects with star formation morphologies
BAT AGN spectroscopic survey - XV: the high frequency radio cores of ultra-hard X-ray selected AGN
We have conducted 22 GHz radio imaging at 1 arcsec resolution of 100 low-redshift AGN selected at 14–195 keV by the Swift-BAT. We find a radio core detection fraction of 96 per cent, much higher than lower frequency radio surveys. Of the 96 radio-detected AGN, 55 have compact morphologies, 30 have morphologies consistent with nuclear star formation, and 11 have sub-kpc to kpc-scale jets. We find that the total radio power does not distinguish between nuclear star formation and jets as the origin of the radio emission. For 87 objects, we use optical spectroscopy to test whether AGN physical parameters are distinct between radio morphological types. We find that X-ray luminosities tend to be higher if the 22 GHz morphology is jet-like, but find no significant difference in other physical parameters. We find that the relationship between the X-ray and core radio luminosities is consistent with the L_R/L_X ∼ 10⁻⁵ of coronally active stars. We further find that the canonical fundamental planes of black hole activity systematically overpredict our radio luminosities, particularly for objects with star formation morphologies
BASS XXXIV: A Catalog of the Nuclear Mm-wave Continuum Emission Properties of AGNs Constrained on Scales 100--200 pc
We present a catalog of the millimeter-wave (mm-wave) continuum properties of
98 nearby ( 0.05) active galactic nuclei (AGNs) selected from the 70-month
Swift/BAT hard X-ray catalog that have precisely determined X-ray spectral
properties and subarcsec-resolution ALMA Band-6 (211--275 GHz) observations as
of 2021 April. Due to the hard-X-ray ( 10 keV) selection, the sample is
nearly unbiased for obscured systems at least up to Compton-thick-level
obscuration, and provides the largest number of AGNs with high physical
resolution mm-wave data ( 100--200 pc). Our catalog reports emission
peak coordinates, spectral indices, and peak fluxes and luminosities at 1.3 mm
(230 GHz). Additionally, high-resolution mm-wave images are provided. Using the
images and creating radial surface brightness profiles of mm-wave emission, we
identify emission extending from the central source and isolated blob-like
emission. Flags indicating the presence of these emission features are
tabulated. Among 90 AGNs with significant detections of nuclear emission, 37
AGNs ( 41%) appear to have both or one of extended or blob-like
components. We, in particular, investigate AGNs that show well-resolved mm-wave
components and find that these seem to have a variety of origins (i.e., a jet,
radio lobes, a secondary AGN, stellar clusters, a narrow line region, galaxy
disk, active star-formation regions, and AGN-driven outflows), and some
components have currently unclear origins.Comment: 49 pages, 7 figures, 3 tables, accepted for publication in ApJ
La experiencia religiosa desde el proceso formativo en ciencias religiosas virtual: en el caso de Karollay Carreño Colina
La técnica del relato autobiográfico permite que la experiencia religiosa al ser relatada y compartida no se pierda, ya que esta experiencia humana se adquiere a través de los hechos y vivencias que suceden en la vida del sujeto, en donde la experiencia religiosa se va estructurando como la posibilidad de hacer consiente y manifiesto ese vínculo correlacional con el ser transcendente que es Dios. Tomando el enfoque cualitativo, cuyo estudio es necesariamente la persona y su contexto y la narrativa autobiográfica, lo que se busca en este trabajo, es entrever cómo se vive la experiencia religiosa en el proceso formativo en las aulas virtuales de aprendizaje y cómo ésta se hace consciente en cada persona desde su propio proceso de fe en los AVA De esta manera se inicia la interpretación hermenéutica teológica del relato autobiográfico de la experiencia religiosa en el proceso formativo en la Licenciatura en Ciencias Religiosas Virtual, describiendo los momentos existenciales y formativos que han favorecido el acontecer de dicha experiencia, evidenciando que ésta es una realidad que se vive dentro de la virtualidad, ya que en muchos momentos se piensa que los ambientes virtuales de aprendizaje AVA, son lugares fríos, mediados por las tecnologías, en donde la experiencia religiosa no puede llegar a trasmitirse, pero estos son lugares en donde realmente se pueden tener experiencias religiosas realmente significativas, requiriendo una atención muy especial para comprender que tras el ambiente virtual, hay y se pueden dar nuevas formas de vivir la religión y la espiritualidad, por ello tan importante el relato autobiográfico. Conforme a lo anterior, se puede evidenciar la experiencia humana como lugar donde acontece la experiencia de Dios, convirtiéndose así el relato autobiográfico en una técnica o camino donde se expresa dicha experiencia y donde los ambientes virtuales de aprendizaje AVA, se articulan como nuevos contextos donde dicha experiencia debe hacerse actual, para contribuir a procesos de formación integral permanente de estudiantes y docentes en la licenciatura en Ciencias Religiosas. Ahora bien, todas las personas tienen historias que contar, que al biografiarlas, se convierten en autores de su propio relato, en donde ponen de manifiesto no solo sus vidas, sino también aquello que los caracteriza, al tiempo que se convierte en un medio para transmitir la experiencia religiosa. Autorelatarse supone entonces compartir la vida y es que la experiencia humana nace en lo profundo del ser, en esa la relación de encuentro con quien le trasciende.An autobiographical storytelling technique allows a religious experience to be told and shared, Keeping it alive since, this human experience is achieved through personal life lessons that every human being has. So, this religious experience is put together to build up the possibility to be conscious about the correlational tie with God and put it forth. From a qualitative approach, which necessary focuses on the person and his/her context and the autobiographical narrative, what this paper looks for is to see how the religious experience is lived in Virtual Training Rooms learning processes, how every person, from their personal procedure, gets conscious about their own faith process. This way, the theological hermeneutics interpretation of religious autobiographical experiences in the Virtual Religious Science Degree is introduced, describing existential and educational moments that have favored these experiences, showing the reality lived from virtuality, considering that these virtual learning environment (VLE) are indifferent and influenced by technologies, where religious experiences cannot be transmitted, although these places are where you can really have a significant religious experience, it is required a special attention to understand that, behind a virtual circle there are new ways to experience religion and spirituality, that is why autobiographical stories are so relevant. In agreement on what is expressed above, it is evident that the human experience, as a space to experience God, has turned the autobiographical storytelling into a technique or way to express it, where virtual learning environment (VLE) are assembled like new context where that experience must be current to contribute on students and Religious Science teachers comprehensive and permanent training process. Having said that, everyone of us has stories to tell so, who write them turn into their own storytellers, where their lives express not only what they have gone through but what typifies them, at the same time these expressions become the means to share religious experiences. To tell your own story supposes that sharing life is a human experience that was boom at the bottom of your inner self, stemming from convergence and transcendence.Licenciado (a) en Ciencias ReligiosasPregrad
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 July 2014. This paper describes the second data release from
this phase, and the fourteenth from SDSS overall (making this, Data Release
Fourteen or DR14). This release makes public data taken by SDSS-IV in its first
two years of operation (July 2014-2016). 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 (eBOSS); 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 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
website (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.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14
happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov
2017 (this is the "post-print" and "post-proofs" version; minor corrections
only from v1, and most of errors found in proofs corrected