Motivated by the current controversy over the redshift distribution and physical properties of luminous (sub-)mm sources, we have undertaken a new study of the brightest sample of unlensed (sub-)mm ...sources with pre-ALMA interferometric follow-up in the COSMOS field. Exploiting the very latest multi-frequency supporting data, we find that this sample displays a redshift distribution indistinguishable from that of the lensed sources uncovered with the South Pole Telescope (SPT), with z_median ~ 3.5. We also find that, over the redshift range z ~ 2-6 the median stellar mass of the most luminous (sub-)mm sources is M_* ~ 3 * 10^11 M_odot, yielding a typical specific star-formation rate sSFR ~ 3 Gyr^-1. Consistent with recent ALMA and SMA studies, we confirm that source blending is not a serious issue in the study of luminous (sub-)mm sources uncovered by ground-based, single-dish surveys; only ~ 10-15% of bright (S_850 ~ 5 - 10 mJy) (sub-)mm sources arise from significant (i.e. >20%) blends, and so our conclusions are largely unaffected by whether we adopt the original single-dish mm/sub-mm flux-densities/positions, or the interferometric data. Our results suggest that apparent disagreements over the redshift distribution of (sub-)mm sources are a result of "down-sizing" in dust-enshrouded star-formation, consistent with existing knowledge of the star-formation histories of massive galaxies. They also indicate that extreme star-forming galaxies at high redshift are, on average, subject to the same star-formation rate-limiting processes as less luminous objects, and lie on the "main sequence" of star-forming galaxies at z>3.
We present the serendipitous ALMA detection of a faint submillimeter galaxy (SMG) lensed by a foreground z~1 galaxy. By optimizing the source detection to deblend the system, we accurately build the ...full spectral energy distribution of the distant galaxy from the I814 band to radio wavelengths. It is extremely red, with a I-K colour larger than 2.5. We estimate a photometric redshift of 3.28 and determine the physical parameters. The distant galaxy turns out to be magnified by the foreground lens by a factor of ~1.5, which implies an intrinsic Ks-band magnitude of ~24.5, a submillimeter flux at 870um of ~2.5 mJy and a SFR of ~150-300Msun/yr, depending on the adopted tracer. These values place our source towards the faint end of the distribution of observed SMGs, and in particular among the still few faint SMGs with a fully characterized spectral energy distribution, which allows us not only to accurately estimate its redshift but also to measure its stellar mass and other physical properties. The galaxy studied in this work is a representative of the population of faint SMGs, of which only few objects are known to date, that are undetected in optical and therefore are not typically accounted for when measuring the cosmic star formation history (SFH). This faint galaxy population thus likely represents an important and missing piece in our understanding of the cosmic SFH. Its observation and characterization is of major importance to achieve a solid picture of galaxy evolution.
Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that is diagnosed in approximately 15% of all human breast cancer (BrCa) patients. Currently, no targeted therapies ...exist for this subtype of BrCa and prognosis remains poor. Our laboratory has previously identified a proliferation/DNA repair/cell cycle gene signature (Tag signature) that is characteristic of human TNBC. We hypothesize that targeting the dysregulated biological networks in the Tag gene signature will lead to the identification of improved combination therapies for TNBC.
Cross-species genomic analysis was used to identify human breast cancer cell lines that express the Tag signature. Knock-down of the up-regulated genes in the Tag signature by siRNA identified several genes that are critical for TNBC cell growth. Small molecule inhibitors to two of these genes were analyzed, alone and in combination, for their effects on cell proliferation, cell cycle, and apoptosis in vitro and tumor growth in vivo. Synergy between the two drugs was analyzed by the Chou-Talalay method.
A custom siRNA screen was used to identify targets within the Tag signature that are critical for growth of TNBC cells. Ribonucleotide reductase 1 and 2 (RRM1 and 2) and checkpoint kinase 1 (CHK1) were found to be critical targets for TNBC cell survival. Combination therapy, to simultaneously attenuate cell cycle checkpoint control through inhibition of CHK1 while inducing DNA damage with gemcitabine, improved therapeutic efficacy in vitro and in xenograft models of TNBC.
This combination therapy may have translational value for patients with TNBC and improve therapeutic response for this aggressive form of breast cancer.
We present Keck-Adaptive Optics and Hubble Space Telescope high resolution near-infrared (IR) imaging for 500 um-bright candidate lensing systems identified by the Herschel Multi-tiered ...Extra-galactic Survey (HerMES) and Herschel Astrophysical Terahertz Survey (H-ATLAS). Out of 87 candidates with near-IR imaging, 15 (~17%) display clear near-IR lensing morphologies. We present near-IR lens models to reconstruct and recover basic rest-frame optical morphological properties of the background galaxies from 12 new systems. Sources with the largest near-IR magnification factors also tend to be the most compact, consistent with the size bias predicted from simulations and pre- vious lensing models for sub-millimeter galaxies. For four new sources that also have high-resolution sub-mm maps, we test for differential lensing between the stellar and dust components and find that the 880 um magnification factor (u_880) is ~1.5 times higher than the near-IR magnification factor (u_NIR), on average. We also find that the stellar emission is ~2 times more extended in size than dust. The rest-frame optical properties of our sample of Herschel-selected lensed SMGs are consistent with those of unlensed SMGs, which suggests that the two populations are similar.
We study the 850um emission in X-ray selected AGN in the 2 sq-deg COSMOS field using new data from the SCUBA-2 Cosmology Legacy Survey. We find 19 850um bright X-ray AGN in a high-sensitivity region ...covering 0.89 sq-deg with flux densities of S850=4-10 mJy. The 19 AGN span the full range in redshift and hard X-ray luminosity covered by the sample - 0.7<z<3.5 and 43.2<log10(LX) <45. We report a highly significant stacked 850um detection of a hard X-ray flux-limited population of 699 z>1 X-ray AGN - S850=0.71+/-0.08mJy. We explore trends in the stacked 850um flux densities with redshift, finding no evolution in the average cold dust emission over the redshift range probed. For Type 1 AGN, there is no significant correlation between the stacked 850um flux and hard X-ray luminosity. However, in Type 2 AGN the stacked submm flux is a factor of 2 higher at high luminosities. When averaging over all X-ray luminosities, no significant differences are found in the stacked submm fluxes of Type 1 and Type 2 AGN as well as AGN separated on the basis of X-ray hardness ratios and optical-to-infrared colours. However, at log10(LX) >44.4, dependences in average submm flux on the optical-to-infrared colours become more pronounced. We argue that these high luminosity AGN represent a transition from a secular to a merger-driven evolutionary phase where the star formation rates and accretion luminosities are more tightly coupled. Stacked AGN 850um fluxes are compared to the stacked fluxes of a mass-matched sample of K-band selected non-AGN galaxies. We find that at 10.5<log10(M*/M0)<11.5, the non-AGN 850um fluxes are 1.5-2x higher than in Type 2 AGN of equivalent mass. We suggest these differences are due to the presence of massive dusty, red starburst galaxies in the K-band selected non-AGN sample, which are not present in optically selected catalogues covering a smaller area.
We describe a far infrared survey of the Coma cluster and the galaxy filament it resides within. Our survey covers an area of \(\sim\)150 deg\(^2\) observed by \(Herschel\) H-ATLAS in five bands at ...100, 160, 250, 350 and 500\(\mu\)m. The SDSS spectroscopic survey (\(m_{r} \le 17.8)\) is used to define an area (within the Virial radius) and redshift selected (\(4268 < v < 9700\) km s\(^{-1}\)) sample of 744 Coma cluster galaxies - the Coma Cluster Catalogue (CCC). For comparison we also define a sample of 951 galaxies in the connecting filament - the Coma Filament Catalogue (CFC). The optical positions and parameters are used to define appropriate apertures to measure each galaxy's far infrared emission. We have detected 99 of 744 (13\%) and 422 of 951 (44\%) of the cluster and filament galaxies in the SPIRE 250\(\mu\)m band. We consider the relative detection rates of galaxies of different morphological types finding that it is only the S0/Sa population that shows clear differences between the cluster and filament. We find no differences between the dust masses and temperatures of cluster and filament galaxies with the exception of early type galaxy dust temperatures, which are significantly hotter in the cluster than in the filament (X-ray heating?). From a chemical evolution model we find no evidence for different evolutionary processes (gas loss or infall) between galaxies in the cluster and filament.
We present high-resolution (0.3'') ALMA 870um imaging of 52 sub-millimeter galaxies (SMGs) in the Ultra Deep Survey (UDS) field and investigate the size and morphology of the sub-millimeter (sub-mm) ...emission on 2-10kpc scales. We derive a median intrinsic angular size of FWHM=0.30\(\pm\)0.04'' for the 23 SMGs in the sample detected at a signal-to-noise ratio (SNR) >10. Using the photometric redshifts of the SMGs we show that this corresponds to a median physical half-light diameter of 2.4\(\pm\)0.2kpc. A stacking analysis of the SMGs detected at an SNR <10 shows they have sizes consistent with the 870um-bright SMGs in the sample. We compare our results to the sizes of SMGs derived from other multi-wavelength studies, and show that the rest-frame ~250um sizes of SMGs are consistent with studies of resolved 12CO (J=3-2 to 7-6) emission lines, but that sizes derived from 1.4GHz imaging appear to be approximately two times larger on average, which we attribute to cosmic ray diffusion. The rest-frame optical sizes of SMGs are around four times larger than the sub-millimeter sizes, indicating that the star formation in these galaxies is compact relative to the pre-existing stellar distribution. The size of the starburst region in SMGs is consistent with the majority of the star formation occurring in a central region, a few kpc in extent, with a median star formation rate surface density of 90\(\pm\)30Msol/yr/kpc\(^2\), which may suggest that we are witnessing an intense period of bulge growth in these galaxies.
We analyze photometric observations of the three main-belt asteroids 350 Ornamenta, 771 Libera, and 984 Gretia, conducted over a twelve-year interval. Our data and those of other authors allow us to ...determine pole and shape models using the lightcurve inversion technique. In all three cases, a single pole solution was obtained without any significant mirror solution: Ornamenta – $P = 9.180\,414$ h, $\lambda_{\rm p} = 184\degr$, $\beta_{\rm p} = -29\degr$ Libera – $P = 5.890\,423$ h, $\lambda_{\rm p} = 64\degr$, $\beta_{\rm p} = -78\degr$ Gretia – $P = 5.778\,025$ h, $\lambda_{\rm p} = 245\degr$, $\beta_{\rm p} = +52\degr$. This analysis and the development of asteroid models increase the set of asteroids with known spin and shape parameters, which consists of only around 100 objects.
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