33 research outputs found
Modelling high resolution ALMA observations of strongly lensed highly star forming galaxies detected by <i>Herschel</i>
We have modelled ∼ 0.1 arcsec resolution ALMA imaging of six strong gravitationally lensed galaxies detected by the Herschel Space Observatory. Our modelling recovers mass properties of the lensing galaxies and, by determining magnification factors, intrinsic properties of the lensed sub-millimetre sources. We find that the lensed galaxies all have high ratios of star formation rate to dust mass, consistent with or higher than the mean ratio for high redshift sub-millimetre galaxies and low redshift ultra-luminous infra-red galaxies. Source reconstruction reveals that most galaxies exhibit disturbed morphologies. Both the cleaned image plane data and the directly observed interferometric visibilities have been modelled, enabling comparison of both approaches. In the majority of cases, the recovered lens models are consistent between methods, all six having mass density profiles that are close to isothermal. However, one system with poor signal to noise shows mildly significant differences
AMYLOIDOSIS AND INFLAMMATORY BOWEL DISEASE: FACT OR MITH?
Inflammatory Bowel Disease (IBD), which includes both Crohn's Disease (CD) and Ulcerative Colitis (UC), is a chronic idiopathic inflammatory disorder affecting the gastrointestinal tract. Extraintestinal manifestations (EIM) are common in patients with IBD, and occur in 6-47% of patients with CD or UC. EIM can involve organs other than the gastrointestinal tract such as skin, eyes, joints, biliary tract and kidneis. Renal and urinary involvement particularly occurs in 4-23% of patients with IBD. Among the renal complications of IBD, seconfary amyloidosis (AA-type, AAA) is a rare but serious complication. renal amyloidosis has been proven to be the most common lethal manifestation of IBD-associated amyloidosis, since renal involvement rapidly leads to end-stage renal failure. A few studies suggest that AAA is more prevalent in CD than in UC, mainly occurring in male patients with an extensive long-lasting and penetrating ddisease pattern. The therapeutic approaches of IBD-associated AAA are based both on control of the chronic inflammatory process that causes the production and storage of serum amyloid A (SAA), which is a precursor of the amyloid, as well as on destabilizing amyloid fibrils so that they can no longer maintain their pleated sheet configuration; however, in patients with end-stage renal disease, the only therapeutic options still available are hemodyalisis and renal transplantation. Whether effective treatment exists for AAA remain controversial
COULD THE ENDOSCOPIC RESECTION OF A LARGE RECTAL LEIOMYOMA BE AN EFFETCIVE AND SAFE TECHNIQUE?
Summary. Rectal leiomyomas are a rare conditions, with low reported incidence in literature and constitute
about 0.1% of rectal tumours; in fact rectal leiomyomas occur in approximately 1 out of 2000-3000 rectal
tumors. We report on a patient with a 3 cm semi-pedunculated colonic leiomyoma, which was successfully
removed by endoscopic polypectomy after normal saline-epinephrine submucosal injection. When we encounter
a tumor during a colonoscopic examination, we usually evaluate the tumor carefully and perform an
endoscopic resection when we judge it is appropriate. When a symptomatic smooth muscle tumors smaller
than 2 cm are incidentally found on colonoscopy, surgical resection is unnecessary. Furthermore, if a tumor
can be lifted with a snare and it is either pedunculated or semi-pedunculated, endoscopic resection might be a
safe option. For those tumors with wide-based or exoluminal growth, endoscopic removal should be avoided
due to the higher risks of bleeding and perforation. The histological findings of the resected tumor are important.
If there is any malignant element that can not be completely eradicated, we would suggest surgical
treatment. We believe our process allows to avoid unnecessary surgery and reduces medical costs
Herschel-ATLAS : The spatial clustering of low and high redshift submillimetre galaxies
We present measurements of the angular correlation function of sub-millimeter (sub-mm) galaxies (SMGs) identified in four out of the five fields of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) − GAMA-9h, GAMA-12h, GAMA-15h and NGP − with flux densities S250μm>30 mJy at 250 μm. We show that galaxies selected at this wavelength trace the underlying matter distribution differently at low and high redshifts. We study the evolution of the clustering finding that at low redshifts sub-mm galaxies exhibit clustering strengths of r0 ∼ 2 − 3 h−1Mpc, below z < 0.3. At high redshifts, on the other hand, we find that sub-mm galaxies are more strongly clustered with correlation lengths r0 = 8.1 ± 0.5, 8.8 ± 0.8 and 13.9 ± 3.9 h−1Mpc at z = 1 − 2, 2 − 3 and 3 − 5, respectively. We show that sub-mm galaxies across the redshift range 1 < z < 5, typically reside in dark-matter halos of mass of the order of ∼ 1012.5 − 1013.0h−1M⊙ and are consistent with being the progenitors of local massive elliptical galaxies that we see in the local Universe
An ALMA survey of the SCUBA-2 Cosmology Legacy Survey UKIDSS/UDS field: halo masses for submillimetre galaxies
We present an analysis of the spatial clustering of a large sample of high-resolution, interferometically identified, submillimetre galaxies (SMGs). We measure the projected cross-correlation function of ∼350 SMGs in the UKIDSS Ultra Deep-Survey Field across a redshift range of z = 1.5–3 utilizing a method that incorporates the uncertainties in the redshift measurements for both the SMGs and cross-correlated galaxies through sampling their full probability distribution functions. By measuring the absolute linear bias of the SMGs, we derive halo masses of log10(Mhalo[h−1M⊙]) ∼ 12.8 with no evidence of evolution in the halo masses with redshift, contrary to some previous work. From considering models of halo mass growth rates, we predict that the SMGs will reside in haloes of mass log10(Mhalo[h−1M⊙]) ∼ 13.2 at z = 0, consistent with the expectation that the majority of z = 1.5–3 SMGs will evolve into present-day spheroidal galaxies. Finally, comparing to models of stellar-to-halo mass ratios, we show that SMGs may correspond to systems that are maximally efficient at converting their gas reservoirs into stars. We compare them to a simple model for gas cooling in haloes that suggests that the unique properties of the SMG population, including their high levels of star formation and their redshift distribution, are a result of the SMGs being the most massive galaxies that are still able to accrete cool gas from their surrounding intragalactic medium
ALMA observations of lensed Herschel sources: testing the dark matter halo paradigm
With the advent of wide-area submillimetre surveys, a large number of high-redshift gravitationally lensed dusty star-forming galaxies have been revealed. Because of the simplicity of the selection criteria for candidate lensed sources in such surveys, identified as those with S500 μm > 100 mJy, uncertainties associated with the modelling of the selection function are expunged. The combination of these attributes makes submillimetre surveys ideal for the study of strong lens statistics. We carried out a pilot study of the lensing statistics of submillimetre-selected sources by making observations with the Atacama Large Millimeter Array (ALMA) of a sample of strongly lensed sources selected from surveys carried out with the Herschel Space Observatory. We attempted to reproduce the distribution of image separations for the lensed sources using a halo mass function taken from a numerical simulation that contains both dark matter and baryons. We used three different density distributions, one based on analytical fits to the haloes formed in the EAGLE simulation and two density distributions [Singular Isothermal Sphere (SIS) and SISSA] that have been used before in lensing studies. We found that we could reproduce the observed distribution with all three density distributions, as long as we imposed an upper mass transition of ∼1013 M⊙ for the SIS and SISSA models, above which we assumed that the density distribution could be represented by a Navarro–Frenk–White profile. We show that we would need a sample of ∼500 lensed sources to distinguish between the density distributions, which is practical given the predicted number of lensed sources in the Herschel surveys
Modelling high-resolution ALMA observations of strongly lensed dusty star-forming galaxies detected by Herschel
We present modelling of ∼0.1 arcsec resolution Atacama Large Millimetre/submillimetre Array imaging of seven strong gravitationally lensed galaxies detected by the Herschel Space Observatory. Four of these systems are galaxy–galaxy strong lenses, with the remaining three being group-scale lenses. Through careful modelling of visibilities, we infer the mass profiles of the lensing galaxies and by determining the magnification factors, we investigate the intrinsic properties and morphologies of the lensed submillimetre sources. We find that these submillimetre sources all have ratios of star formation rate to dust mass that are consistent with, or in excess of, the mean ratio for high-redshift submillimetre galaxies and low redshift ultra-luminous infrared galaxies. Reconstructions of the background sources reveal that the majority of our sample display disturbed morphologies. The majority of our lens models have mass density slopes close to isothermal, but some systems show significant differences
The COSMOS-Web ring: in-depth characterization of an Einstein ring lensing system at z~2
Aims. We provide an in-depth analysis of the COSMOS-Web ring, an Einstein
ring at z=2 that we serendipitously discovered in the COSMOS-Web survey and
possibly the most distant lens discovered to date.
Methods. We extract the visible and NIR photometry from more than 25 bands
and we derive the photometric redshifts and physical properties of both the
lens and the source with three different SED fitting codes. Using JWST/NIRCam
images, we also produce two lens models to (i) recover the total mass of the
lens, (ii) derive the magnification of the system, (iii) reconstruct the
morphology of the lensed source, and (iv) measure the slope of the total mass
density profile of the lens.
Results. The lens is a very massive and quiescent (sSFR < 10^(-13) yr-1)
elliptical galaxy at z = 2.02 \pm 0.02 with a total mass Mtot(<thetaE) = (3.66
\pm 0.36) x 10^11 Msun and a stellar mass M* = (1.37 \pm 0.14) x 10^11 Msun.
Compared to SHMRs from the literature, we find that the total mass is
consistent with the presence of a DM halo of mass Mh = 1.09^(+1.46)_(-0.57) x
10^13 Msun. In addition, the background source is a M* = (1.26 \pm 0.17) x
10^10 Msun star-forming galaxy (SFR=(78 \pm 15) Msun/yr) at z = 5.48 \pm 0.06.
Its reconstructed morphology shows two components with different colors. Dust
attenuation values from SED fitting and nearby detections in the FIR also
suggest it could be partially dust-obscured.
Conclusions. We find the lens at z=2. Its total, stellar, and DM halo masses
are consistent within the Einstein ring, so we do not need any unexpected
changes in our description of the lens (e.g. change its IMF or include a
non-negligible gas contribution). The most likely solution for the lensed
source is at z = 5.5. Its reconstructed morphology is complex and highly
wavelength dependent, possibly because it is a merger or a main sequence galaxy
with a heterogeneous dust distribution.Comment: 16 pages, submitted to A&
Bright Extragalactic ALMA Redshift Survey (BEARS) III: Detailed study of emission lines from 71 Herschel targets
We analyse the molecular and atomic emission lines of 71 bright
Herschel-selected galaxies between redshifts 1.4 to 4.6 detected by the Atacama
Large Millimetre/submillimetre Array. These lines include a total of 156 CO, [C
I], and H2O emission lines. For 46 galaxies, we detect two transitions of CO
lines, and for these galaxies we find gas properties similar to those of other
dusty star-forming galaxy (DSFG) samples. A comparison to photo-dissociation
models suggests that most of Herschel-selected galaxies have similar
interstellar medium conditions as local infrared-luminous galaxies and
high-redshift DSFGs, although with denser gas and more intense far-ultraviolet
radiation fields than normal star-forming galaxies. The line luminosities agree
with the luminosity scaling relations across five orders of magnitude, although
the star-formation and gas surface density distributions (i.e.,
Schmidt-Kennicutt relation) suggest a different star-formation phase in our
galaxies (and other DSFGs) compared to local and low-redshift gas-rich, normal
star-forming systems. The gas-to-dust ratios of these galaxies are similar to
Milky Way values, with no apparent redshift evolution. Four of 46 sources
appear to have CO line ratios in excess of the expected maximum (thermalized)
profile, suggesting a rare phase in the evolution of DSFGs. Finally, we create
a deep stacked spectrum over a wide rest-frame frequency (220-890 GHz) that
reveals faint transitions from HCN and CH, in line with previous stacking
experiments.Comment: 30 pages, 17 figures, accepted for publication in Monthly Notices of
the Royal Astronomical Society Main Journal. Comments are warmly welcome
Characterisation of <i>Herschel</i>-selected strong lens candidates through <i>HST</i> and sub-mm/mm observations
We have carried out HST snapshot observations at 1.1 μm of 281 candidate strongly lensed galaxies identified in the wide-area extragalactic surveys conducted with the Herschel space observatory. Our candidates comprise systems with flux densities at 500 μm S500 ≥ 80 mJy. We model and subtract the surface brightness distribution for 130 systems, where we identify a candidate for the foreground lens candidate. After combining visual inspection, archival high-resolution observations, and lens subtraction, we divide the systems into different classes according to their lensing likelihood. We confirm 65 systems to be lensed. Of these, 30 are new discoveries. We successfully perform lens modelling and source reconstruction on 23 systems, where the foreground lenses are isolated galaxies and the background sources are detected in the HST images. All the systems are successfully modelled as a singular isothermal ellipsoid. The Einstein radii of the lenses and the magnifications of the background sources are consistent with previous studies. However, the background source circularised radii (between 0.34 kpc and 1.30 kpc) are ∼3 times smaller than the ones measured in the sub-mm/mm for a similarly selected and partially overlapping sample. We compare our lenses with those in the SLACS survey, confirming that our lens-independent selection is more effective at picking up fainter and diffuse galaxies and group lenses. This sample represents the first step towards characterising the near-IR properties and stellar masses of the gravitationally lensed dusty star-forming galaxies