1,221 research outputs found
Galaxy cluster mergers as triggers for the formation of jellyfish galaxies: case study of the A901/2 system
The A901/2 system is a rare case of galaxy cluster interaction, in which two
galaxy clusters and two smaller groups are seen in route of collision with each
other simultaneously. Within each of the four substructures, several galaxies
with features indicative of jellyfish morphologies have been observed. In this
paper, we propose a hydrodynamic model for the merger as a whole, compatible
with its diffuse X-ray emission, and correlate the gas properties in this model
with the locations of the jellyfish galaxy candidates in the real system. We
find that jellyfish galaxies seem to be preferentially located near a boundary
inside each subcluster where diffuse gas moving along with the subcluster and
diffuse gas from the remainder of the system meet. The velocity change in those
boundaries is such that a factor of up to 1000 increase in the ram
pressure takes place within a few hundred kpc, which could trigger the high
rate of gas loss necessary for a jellyfish morphology to emerge. A theoretical
treatment of ram pressure stripping in the environment of galaxy cluster
mergers has not been presented in the literature so far; we propose that this
could be a common scenario for the formation of jellyfish morphologies in such
systems.Comment: Accepted for publication in MNRAS. 10 pages, 9 figure
The impact of environmental effects on AGN: a decline in the incidence of ionized outflows
AGN have been generally considered to be less frequent in denser environments
due to the lower number of galaxy-galaxy interactions and/or the removal of
their gas-rich reservoirs by the dense intergalactic medium. However, recent
observational and theoretical works suggest that the effect of ram-pressure
stripping might reduce the angular momentum of their gas, causing it to infall
towards the super massive black hole (SMBH) at their centre, activating the AGN
phase. In this work we explore the connection between environment and nuclear
activity by evaluating the variation in the incidence of ionized outflows in
AGN across different environments. We select a sample of optical AGN
from the Sloan Digital Sky Survey Data Release 13 that we match with the group
catalogue from Lim et al. 2017. We further probe their environment through the
projected distance to the central galaxy of the group/cluster and the projected
surface density to the 5th neighbour (). We find that at lower masses
(M), the fraction of ionized outflows is significantly
lower in satellite (%) than in isolated (%) AGN. The fraction of
outflows in all satellite AGN decreases towards closer distances to the
central, whereas only the lower-mass ones display a significant decline with
. Although this study does not include AGN in the densest regions of
galaxy clusters, our findings suggest that AGN in dense environments accrete
less gas than those in the field potentially due to the removal of the gas
reservoirs via stripping or starvation, consistent with a negative connection
between environment and AGN activity. We propose that the observed change in
the incidence of outflows towards denser regions of groups and clusters could
contribute to the higher gas metallicities of cluster galaxies compared to
field ones, especially at lower masses.Comment: 9 pages, 6 figures, Accepted for publication in Astronomy and
Astrophysic
Wavelength self-calibration and sky subtraction for Fabry–Pérot interferometers: applications to OSIRIS
We describe techniques concerning wavelength calibration and sky subtraction to maximize the scientific utility of data from tunable filter instruments. While we specifically address data from the Optical System for Imaging and low Resolution Integrated Spectroscopy instrument (OSIRIS) on the 10.4-m Gran Telescopio Canarias telescope, our discussion is generalizable to data from other tunable filter instruments. A key aspect of our methodology is a coordinate transformation to polar coordinates, which simplifies matters when the tunable filter data are circularly symmetric around the optical centre. First, we present a method for rectifying inaccuracies in the wavelength calibration using OH sky emission rings. Using this technique, we improve the absolute wavelength calibration from an accuracy of ∼5 to 1 Å, equivalent to ∼7 per cent of our instrumental resolution, for 95 per cent of our data. Then, we discuss a new way to estimate the background sky emission by median filtering in polar coordinates. This method suppresses contributions to the sky background from the outer envelopes of distant galaxies, maximizing the fluxes of sources measured in the corresponding sky-subtracted images. We demonstrate for data tuned to a central wavelength of 7615 Å that galaxy fluxes in the new sky-subtracted image are ∼37 per cent higher, versus a sky-subtracted image from existing methods for OSIRIS tunable filter data
Physics of ULIRGs with MUSE and ALMA: The PUMA project: I. Properties of the survey and first MUSE data results
Ultraluminous infrared galaxies (ULIRGs) are characterised by extreme
starburst (SB) and AGN activity, and are therefore ideal laboratories for
studying the outflow phenomena. We have recently started a project called
Physics of ULIRGs with MUSE and ALMA (PUMA), which is a survey of 25 nearby (z
< 0.165) ULIRGs observed with the integral field spectrograph MUSE and the
interferometer ALMA. This sample includes systems with both AGN and SB nuclear
activity in the pre- and post-coalescence phases of major mergers. The main
goals of the project are to study the prevalence of multi-phase outflows as a
function of the galaxy properties, to constrain the driving mechanisms of the
outflows (e.g. distinguish between SB and AGN winds), and to identify feedback
effects on the host galaxy. In this first paper, we present details on the
sample selection, MUSE observations, and derive first data products. MUSE data
were analysed to study the dynamical status of each of the 21 ULIRGs observed
so far, taking the stellar kinematics and the morphological properties inferred
from MUSE narrow-band images into account. We also located the ULIRG nuclei,
using near-IR (HST) and mm (ALMA) data, and studied their optical spectra to
infer the ionisation state through BPT diagnostics, and outflows in both
ionised and neutral gas. We show that the morphological and stellar kinematic
classifications are consistent: post-coalescence systems are more likely
associated with ordered motions, while interacting (binary) systems are
dominated by non-ordered and streaming motions. We also find broad and
asymmetric [OIII] and NaID profiles in almost all nuclear spectra, with line
widths in the range 300-2000 km/s, possibly associated with AGN- and SB-driven
winds. This result reinforces previous findings that indicated that outflows
are ubiquitous during the pre- and post-coalescence phases of major mergers.ERC
STF
MUSE view of Arp220: Kpc-scale multi-phase outflow and evidence for positive feedback
Arp220 is the nearest and prototypical ULIRG, and shows evidence of pc-scale
molecular outflows in its nuclear regions and strongly perturbed ionised gas
kinematics on kpc scales. It is therefore the ideal system for investigating
outflows and feedback phenomena in details. We investigate the feedback effects
on the Arp220 ISM, deriving a detailed picture of the atomic gas in terms of
physical and kinematic properties, with a spatial resolution never obtained
before (0.56", i.e. ~ 210 pc). We use optical IFS observations from VLT/MUSE-AO
to obtain spatially resolved stellar and gas kinematics, for both ionised ([N
II]6583) and neutral (Na ID5891,96) components; we also derive dust
attenuation, electron density, ionisation conditions and hydrogen column
density maps to characterise the ISM properties. Arp220 kinematics reveal the
presence of a disturbed, kpc-scale disk in the innermost nuclear regions, and
highly perturbed, multi-phase (neutral and ionised) gas along the minor-axis of
the disk, which we interpret as a galactic-scale outflow emerging from the
Arp220 eastern nucleus. This outflow involves velocities up to ~ 1000 km/s at
galactocentric distances of ~ 5 kpc, and has a mass rate of ~ 50 Msun/yr, and
kinetic and momentum power of ~ 1e43 erg/s and ~ 1e35 dyne, respectively. The
inferred energetics do not allow us to distinguish the origin of the outflows,
i.e. whether they are AGN-driven or starburst-driven. We also present evidence
for enhanced star formation at the edges of - and within - the outflow, with a
star formation rate SFR ~ 5 Msun/yr (i.e. ~ 2% of the total SFR). Our findings
suggest the presence of powerful winds in Arp220: they might be capable of
removing or heating large amounts of gas from the host ("negative feedback"),
but could be also responsible for triggering star formation ("positive
feedback").STFC
ER
The host galaxies of luminous type 2 AGNs at z ~ 0.3-0.4
We study the morphological and structural properties of the host galaxies associated with 57 optically selected luminous type 2 active galactic nuclei (AGNs) at z ∼ 0.3–0.4: 16 high-luminosity Seyfert 2 [HLSy2, 8.0 ≤ log(L[OIII]/L⊙)< 8.3] and 41 obscured [QSO2, log(L[OIII]/L⊙)≥ 8.3] quasars. With this work, the total number of QSO2s at z < 1 with parametrized galaxies increases from ∼35 to 76. Our analysis is based on Hubble Space Telescope WFPC2 and ACS images that we fit with GALFIT. HLSy2s and QSO2s show a wide diversity of galaxy hosts. The main difference lies in the higher incidence of highly disturbed systems among QSO2s. This is consistent with a scenario in which galaxy interactions are the dominant mechanism triggering nuclear activity at the highest AGN power. There is a strong dependence of galaxy properties with AGN power (assuming L[OIII] is an adequate proxy). The relative contribution of the spheroidal component to the total galaxy light (B/T) increases with L[OIII]. While systems dominated by the spheroidal component spread across the total range of L[OIII], most disc-dominated galaxies concentrate at log(L[OIII]/L⊙)<8.6. This is expected if more powerful AGNs are powered by more massive black holes which are hosted by more massive bulges or spheroids. The average galaxy sizes (〈re〉) are 5.0 ± 1.5 kpc for HLSy2s and 3.9 ± 0.6 kpc for HLSy2s and QSO2s, respectively. These are significantly smaller than those found for QSO1s and narrow-line radio galaxies at similar z. We put the results of our work in the context of related studies of AGNs with quasar-like luminosities.JUM and MVM acknowledge support from the Spanish former Ministerio de Economía y Competitividad through the grants AYA2012-32295 and AYA2015-64346-C2-2-P. FB acknowledges the support by FCT via the postdoctoral fellowship SFRH/BPD/103958/2014. This work is supported by Fundacao para a Ciencia e a Tecnologia (FCT) through national funds (UID/FIS/04434/2013) and by FEDER through COMPETE2020 (POCI-01-0145-FEDER-007672). FB also acknowledges support from grant AYA2016-77237-C3-1-P from the Spanish Ministry of Economy and Competitiveness (MINECO). JPL acknowledges support from the Spanish Ministerio de Economía y Competitividad through the grant AYA2017-85170-R. BRP acknowledges financial support from the Spanish Ministry of Economy and Competitiveness through grant ESP2015-68964. F.J.C. acknowledges financial support through grant AYA2015-64346-C2-1-P (MINECO/FEDER)
The host galaxies of luminous type 2 AGNs at z ∼ 0.3–0.4
ABSTRACT: We study the morphological and structural properties of the host galaxies associated with 57 optically selected luminous type 2 active galactic nuclei (AGNs) at z ∼ 0.3–0.4: 16 high-luminosity Seyfert 2 [HLSy2, 8.0 ≤ log(L[oIII]/Lʘ) < 8.3] and 41 obscured [QSO2, log(L[O III]/Lʘ) ≥ 8.3] quasars. With this work, the total number of QSO2s at z < 1 with parametrized galaxies increases from ∼35 to 76. Our analysis is based on Hubble Space Telescope WFPC2 and ACS images that we fit with GALFIT. HLSy2s and QSO2s show a wide diversity of galaxy hosts. The main difference lies in the higher incidence of highly disturbed systems among QSO2s. This is consistent with a scenario in which galaxy interactions are the dominant mechanism triggering nuclear activity at the highest AGN power. There is a strong dependence of galaxy properties with AGN power (assuming L[O III] is an adequate proxy). The relative contribution of the spheroidal component to the total galaxy light (B/T) increases with L[O III]. While systems dominated by the spheroidal component spread across the total range of L[O III], most disc-dominated galaxies concentrate at log(L[O III]/Lʘ)JUM and MVM acknowledge support from the Spanish former Ministerio de Economía y Competitividad through the grants AYA2012-32295 and AYA2015-64346-C2-2-P. FB also acknowledges support from grant AYA2016-77237-C3-1-P from the Spanish Ministry of Economy and Competitiveness (MINECO). JPL
acknowledges support from the Spanish Ministerio de Economía y Competitividad through the grant AYA2017-85170-R. BRP acknowledges financial support from the Spanish Ministry of Economy and Competitiveness through grant ESP2015-68964. F.J.C. acknowledges financial support through grant AYA2015-64346-C2-1-P (MINECO/FEDER)
The ultra-dense, interacting environment of a dual AGN at z 3.3 revealed by JWST/NIRSpec IFS
LBQS 0302-0019 is a blue quasar (QSO) at z ~ 3.3, hosting powerful outflows,
and residing in a complex environment consisting of an obscured AGN candidate,
and multiple companions, all within 30 kpc in projection. We use JWST NIRSpec
IFS observations to characterise the ionized gas in this complex system. We
develop a procedure to correct for the spurious oscillations (or 'wiggles') in
NIRSpec single-spaxel spectra, due to the spatial under-sampling of the point
spread function. We perform a quasar-host decomposition with the QDeblend3D
tools, and use multi-component kinematic decomposition of the optical emission
line profiles to infer the physical properties of the emitting gas. The
quasar-host decomposition allows us to identify i) a low-velocity component
possibly tracing a warm rotating disk, with a dynamical mass Mdyn Msun and a rotation-to-random motion ratio /; ii) a spatially unresolved ionised outflow, with a velocity of 1000
km/s and an outflow mass rate of Msun/yr. We also detect eight
interacting companion objects close to LBQS 0302-0019. Optical line ratios
confirm the presence of a second, obscured AGN at kpc of the primary
QSO; the dual AGN dominates the ionization state of the gas in the entire
NIRSpec field-of-view. This work has unveiled with unprecedented detail the
complex environment of this dual AGN, which includes nine interacting
companions (five of which were previously unknown), all within 30 kpc of the
QSO. Our results support a scenario where mergers can trigger dual AGN, and can
be important drivers for rapid early SMBH growth.Comment: 23 pages, 23 figures; accepted for publication by A&
Research-based flow cytometry assays for pathogenic assessment in the human B-cell biology of gene variants revealed in the diagnosis of inborn errors of immunity: a Bruton’s tyrosine kinase case-study
IntroductionInborn errors of immunity (IEI) are an expanding group of rare diseases whose field has been boosted by next-generation sequencing (NGS), revealing several new entities, accelerating routine diagnoses, expanding the number of atypical presentations and generating uncertainties regarding the pathogenic relevance of several novel variants.MethodsResearch laboratories that diagnose and provide support for IEI require accurate, reproducible and sustainable phenotypic, cellular and molecular functional assays to explore the pathogenic consequences of human leukocyte gene variants and contribute to their assessment. We have implemented a set of advanced flow cytometry-based assays to better dissect human B-cell biology in a translational research laboratory. We illustrate the utility of these techniques for the in-depth characterization of a novel (c.1685G>A, p.R562Q) de novo gene variant predicted as probably pathogenic but with no previous insights into the protein and cellular effects, located in the tyrosine kinase domain of the Bruton’s tyrosine kinase (BTK) gene, in an apparently healthy 14-year-old male patient referred to our clinic for an incidental finding of low immunoglobulin (Ig) M levels with no history of recurrent infections.Results and discussionA phenotypic analysis of bone marrow (BM) revealed a slightly high percentage of pre-B-I subset in BM, with no blockage at this stage, as typically observed in classical X-linked agammaglobulinemia (XLA) patients. The phenotypic analysis in peripheral blood also revealed reduced absolute numbers of B cells, all pre-germinal center maturation stages, together with reduced but detectable numbers of different memory and plasma cell isotypes. The R562Q variant allows Btk expression and normal activation of anti-IgM-induced phosphorylation of Y551 but diminished autophosphorylation at Y223 after anti IgM and CXCL12 stimulation. Lastly, we explored the potential impact of the variant protein for downstream Btk signaling in B cells. Within the canonical nuclear factor kappa B (NF-κB) activation pathway, normal IκBα degradation occurs after CD40L stimulation in patient and control cells. In contrast, disturbed IκBα degradation and reduced calcium ion (Ca2+) influx occurs on anti-IgM stimulation in the patient’s B cells, suggesting an enzymatic impairment of the mutated tyrosine kinase domain
GA-NIFS: co-evolution within a highly star-forming galaxy group at z=3.7 witnessed by JWST/NIRSpec IFS
We present NIRSpec IFS observations of a galaxy group around the massive
GS_4891 galaxy at z=3.7 in GOODS-South that includes two other two systems,
GS_4891_n to the north and GS_28356 to the east. These observations, obtained
as part of the GTO GA-NIFS program, allow for the first time to study the
spatially resolved properties of the interstellar medium (ISM) and ionized gas
kinematics of a galaxy at this redshift. Leveraging the wide wavelength range
spanned with the high-dispersion grating (with resolving power R=2700)
observations, covering from [OII]3726,29 to
[SII]6716,31, we explore the spatial distribution of
star-formation rate, nebular attenuation and gas metallicity, together with the
mechanisms responsible for the excitation of the ionized gas. GS_4891 presents
a clear gradient of gas metallicity (as traced by 12 + log(O/H)) by more than
0.2dex from the south-east (where a star-forming clump is identified) to the
north-west. The gas metallicity in the less-massive northern system, GS_4891_n,
is also higher by 0.2 dex than at the center of GS_4891, suggesting that
inflows of lower-metallicity gas might be favoured in higher-mass systems. The
kinematic analysis shows that GS_4891 presents velocity gradients in the
ionized gas consistent with rotation. The region between GS_4891 and GS_4891_n
does not present high gas turbulence which, together with the difference in gas
metallicities, suggests that these two systems might be in a pre-merger stage.
Finally, GS_4891 hosts an ionized outflow that extends out to r_out=1.2 kpc
from the nucleus and reaches maximum velocities v_out of approximately 400
km/s. Despite entraining an outflowing mass rate of M_out2Msun/yr, the
low associated mass-loading factor, =0.05, implies that the outflow does
not have a significant impact on the star-formation activity of the galaxy.Comment: Submitted to Astronomy & Astrophysics on September 25th, 202
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