454 research outputs found
Dissecting Galaxies: Separating Star Formation, Shock Excitation and AGN Activity in the Central Region of NGC 613
The most rapidly evolving regions of galaxies often display complex optical
spectra with emission lines excited by massive stars, shocks and accretion onto
supermassive black holes. Standard calibrations (such as for the star formation
rate) cannot be applied to such mixed spectra. In this paper we isolate the
contributions of star formation, shock excitation and active galactic nucleus
(AGN) activity to the emission line luminosities of individual spatially
resolved regions across the central 3 3 kpc region of the active
barred spiral galaxy NGC613. The star formation rate and AGN luminosity
calculated from the decomposed emission line maps are in close agreement with
independent estimates from data at other wavelengths. The star formation
component traces the B-band stellar continuum emission, and the AGN component
forms an ionization cone which is aligned with the nuclear radio jet. The
optical line emission associated with shock excitation is cospatial with strong
and [Fe II] emission and with regions of high ionized gas velocity
dispersion ( km s). The shock component also traces the
outer boundary of the AGN ionization cone and may therefore be produced by
outflowing material interacting with the surrounding interstellar medium. Our
decomposition method makes it possible to determine the properties of star
formation, shock excitation and AGN activity from optical spectra, without
contamination from other ionization mechanisms.Comment: 16 pages, 12 figures. Accepted for publication in MNRA
Searching for an Intermediate Mass Black Hole in the Blue Compact Dwarf galaxy MRK 996
The possibility is explored that accretion on an intermediate mass black hole
contributes to the ionisation of the interstellar medium of the Compact Blue
Dwarf galaxy MRK996. Chandra observations set tight upper limits (99.7 per cent
confidence level) in both the X-ray luminosity of the posited AGN,
Lx(2-10keV)<3e40erg/s, and the black hole mass, <1e4/\lambda Msolar, where
\lambda, is the Eddington ratio. The X-ray luminosity upper limit is
insufficient to explain the high ionisation line [OIV]25.89\mu m, which is
observed in the mid-infrared spectrum of the MRK996 and is proposed as evidence
for AGN activity. This indicates that shocks associated with supernovae
explosions and winds of young stars must be responsible for this line. It is
also found that the properties of the diffuse X-ray emission of MRK996 are
consistent with this scenario, thereby providing direct evidence for shocks
that heat the galaxy's interstellar medium and contribute to its ionisation.Comment: Submitted to MNRA
Pirfenidone in idiopathic pulmonary fibrosis:expert panel discussion on the management of drug-related adverse events
Pirfenidone is currently the only approved therapy for idiopathic pulmonary fibrosis, following studies demonstrating that treatment reduces the decline in lung function and improves progression-free survival. Although generally well tolerated, a minority of patients discontinue therapy due to gastrointestinal and skin-related adverse events (AEs). This review summarizes recommendations based on existing guidelines, research evidence, and consensus opinions of expert authors, with the aim of providing practicing physicians with the specific clinical information needed to educate the patient and better manage pirfenidone-related AEs with continued pirfenidone treatment. The main recommendations to help prevent and/or mitigate gastrointestinal and skin-related AEs include taking pirfenidone during (or after) a meal, avoiding sun exposure, wearing protective clothing, and applying a broad-spectrum sunscreen with high ultraviolet (UV) A and UVB protection. These measures can help optimize AE management, which is key to maintaining patients on an optimal treatment dose.Correction in: Advances in Therapy, Volume 31, Issue 5, pp 575-576 , doi: 10.1007/s12325-014-0118-8</p
AEGIS: Demographics of X-ray and Optically Selected AGNs
We develop a new diagnostic method to classify galaxies into AGN hosts,
star-forming galaxies, and absorption-dominated galaxies by combining the [O
III]/Hbeta ratio with rest-frame U-B color. This can be used to robustly select
AGNs in galaxy samples at intermediate redshifts (z<1). We compare the result
of this optical AGN selection with X-ray selection using a sample of 3150
galaxies with 0.3<z<0.8 and I_AB<22, selected from the DEEP2 Galaxy Redshift
Survey and the All-wavelength Extended Groth Strip International Survey
(AEGIS). Among the 146 X-ray sources in this sample, 58% are classified
optically as emission-line AGNs, the rest as star-forming galaxies or
absorption-dominated galaxies. The latter are also known as "X-ray bright,
optically normal galaxies" (XBONGs). Analysis of the relationship between
optical emission lines and X-ray properties shows that the completeness of
optical AGN selection suffers from dependence on the star formation rate and
the quality of observed spectra. It also shows that XBONGs do not appear to be
a physically distinct population from other X-ray detected, emission-line AGNs.
On the other hand, X-ray AGN selection also has strong bias. About 2/3 of all
emission-line AGNs at L_bol>10^44 erg/s in our sample are not detected in our
200 ks Chandra images, most likely due to moderate or heavy absorption by gas
near the AGN. The 2--7 keV detection rate of Seyfert 2s at z~0.6 suggests that
their column density distribution and Compton-thick fraction are similar to
that of local Seyferts. Multiple sample selection techniques are needed to
obtain as complete a sample as possible.Comment: 24 pages, 14 figures, submitted to ApJ. Version 2 matches the ApJ
accepted version. Sec 3 was reorganized and partly rewritten with one
additional figure (Fig.3
The SAMI Galaxy Survey: observing the environmental quenching of star formation in GAMA groups
We explore the radial distribution of star formation in galaxies in the SAMI Galaxy Survey as a function of their Local Group environment. Using a sample of galaxies in groups (with halo masses less than similar or equal to 10(14) M-circle dot) from the Galaxy And Mass Assembly Survey, we find signatures of environmental quenching in high-mass groups (M-G > 10(12.5) M-circle dot). The mean integrated specific star formation rate (sSFR) of star-forming galaxies in high-mass groups is lower than for galaxies in low-mass groups or those that are ungrouped, with Delta log(sSFR/yr(-1)) = 0.45 +/- 0.07. This difference is seen at all galaxy stellar masses. In high-mass groups, star-forming galaxies more massive than M-* similar to 10(10) M-circle dot have centrally concentrated star formation. These galaxies also lie below the star formation main sequence, which suggests they may be undergoing outside-in quenching. Lower mass galaxies in high-mass groups do not show evidence of concentrated star formation. In groups less massive than M-G = 10(12.5) M-circle dot, we do not observe these trends. In this regime, we find a modest correlation between centrally concentrated star formation and an enhancement in the total star formation rate, consistent with triggered star formation in these galaxies.The SAMI Galaxy Survey is supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013, the Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO), through project number CE110001020, and other participating institutions. M.S.O. acknowledges the funding support from the Australian Research Council (ARC) through a Future Fellowship (FT140100255). J.T.A. acknowledges the award of a Science and Industry Endowment Fund (SIEF) John Stocker Fellowship.
J.v.d.S. is funded under Bland-Hawthorn’s ARC Laureate Fellowship (FL140100278). S.B. acknowledges the funding support from the Australian Research Council through a Future Fellowship (FT140101166). S.K.Y. acknowledges support from the Korean National Research Foundation (2017R1A2A1A05001116) and by the Yonsei University Future Leading Research Initiative (2015-22-0064). C.F. gratefully acknowledges funding provided by the Australian Research Council’s Discovery Projects (grants DP150104329 and DP170100603). Support for A.M.M. is provided by National Aeronautics and Space Adminsitration (NASA) through Hubble Fellowship grant #HST-HF2-51377 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555
The Limits of Responsible Innovation: Exploring Care, Vulnerability and Precision Medicine
Drawing on insights from feminist and Science and Technology Studies writing on care and vulnerability, this paper will critically explore conceptualisations of responsibility, care and vulnerability in relation to contemporary approaches to Responsible Innovation (RI). Drawing on examples of some of the social and ethical challenges of precision medicine, we highlight the on-going, distributed and complex nature of innovation and responsibilities in relation to markets, patient and carer experience and data practices associated with these new technologies to highlight some of the limits of RI. We end by reflecting on the implications of our analysis for the social and ethical challenges of precision medicine and RI more generally
Multi-Scale Stellar Associations across the Star Formation Hierarchy in PHANGS-HST Nearby Galaxies: Methodology and Properties
We develop a method to identify and determine the physical properties of
stellar associations using Hubble Space Telescope (HST) NUV-U-B-V-I imaging of
nearby galaxies from the PHANGS-HST survey. We apply a watershed algorithm to
density maps constructed from point source catalogues Gaussian smoothed to
multiple physical scales from 8 to 64 pc. We develop our method on two galaxies
that span the distance range in the PHANGS-HST sample: NGC 3351 (10 Mpc), NGC
1566 (18 Mpc). We test our algorithm with different parameters such as the
choice of detection band for the point source catalogue (NUV or V), source
density image filtering methods, and absolute magnitude limits. We characterise
the properties of the resulting multi-scale associations, including sizes,
number of tracer stars, number of associations, photometry, as well as ages,
masses, and reddening from Spectral Energy Distribution fitting. Our method
successfully identifies structures that occupy loci in the UBVI colour-colour
diagram consistent with previously published catalogues of clusters and
associations. The median ages of the associations increases from log(age/yr) =
6.6 to log(age/yr) = 6.9 as the spatial scale increases from 8 pc to 64 pc for
both galaxies. We find that the youngest stellar associations, with ages < 3
Myr, indeed closely trace H ii regions in H imaging, and that older
associations are increasingly anti-correlated with the H emission.
Owing to our new method, the PHANGS-HST multi-scale associations provide a far
more complete census of recent star formation activity than found with previous
cluster and compact association catalogues. The method presented here will be
applied to the full sample of 38 PHANGS-HST galaxies.Comment: Submitted to MNRAS. Referee report received with minor comments, and
"request to clarify if the smaller associations are always included in the
larger ones and how this may affect the photometric fitting of the larger
association if the groups have different ages." Revision in progres
British Communists and the 1932 turn to the trade unions
The Comintern’s Third Period, 1928-1934, based on Stalin’s ‘second revolution’ in Russia, capitalist crisis and the claim that social democracy and fascism were twins, generated sectarian, ultra-left politics which proved inimical to Communist activity in trade unions. This article sheds new light on that issue by revisiting three connected episodes: the British party’s (CPGB) renewed turn to the unions, heralded in the January resolution of 1932; the roles Comintern staff and CPGB leader Harry Pollitt, played in this initiative; and the subsequent attempt by Pollitt to revise the politics of union work. This triptych reviews both primary sources and the recent historiography. It argues that some accounts have overestimated the novelty of the January resolution, blurred its meaning, and exaggerated Pollitt’s part in it. The resolution did not attempt to change the line but its application. Its impact was limited. Subsequent bids to go beyond it were muddled and unsuccessful. The 1933 move towards the united front, and the ensuing turn to the popular front, possessed more profound significance in the creation of an effective Communist presence in trade unions than the events of 1931- 1932
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