Strong gravitational lenses are now being routinely discovered in wide-field surveys at (sub-)millimeter wavelengths. We present Submillimeter Array (SMA) high-spatial resolution imaging and Gemini-South and Multiple Mirror Telescope optical spectroscopy of strong lens candidates discovered in the two widest extragalactic surveys conducted by the Herschel Space Observatory: the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) and the Herschel Multi-tiered Extragalactic Survey (HerMES). From a sample of 30 Herschel sources with S 500 > 100 mJy, 21 are strongly lensed (i.e., multiply imaged), 4 are moderately lensed (i.e., singly imaged), and the remainder require additional data to determine their lensing status. We apply a visibility-plane lens modeling technique to the SMA data to recover information about the masses of the lenses as well as the intrinsic (i.e., unlensed) sizes (r half ) and far-infrared luminosities (L FIR ) of the lensed submillimeter galaxies (SMGs). The sample of lenses comprises primarily isolated massive galaxies, but includes some groups and clusters as well. Several of the lenses are located at z lens > 0.7, a redshift regime that is inaccessible to lens searches based on Sloan Digital Sky Survey spectroscopy. The lensed SMGs are amplified by factors that are significantly below statistical model predictions given the 500 µm flux densities of our sample. We speculate that this may reflect a deficiency in our understanding of the intrinsic sizes and luminosities of the brightest SMGs. The lensed SMGs span nearly one decade in L FIR (median L FIR = 7.9 × 10 12 L ) and two decades in FIR luminosity surface density (median Σ FIR = 6.0 × 10 11 L kpc −2 ). The strong lenses in this sample and others identified via (sub-)mm surveys will provide a wealth of information regarding the astrophysics of galaxy formation and evolution over a wide range in redshift.

The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. CitationHamilton, V.E., et al., "Evidence for widespread hydrated minerals on asteroid (101955) Bennu." Nature astronomy 3, 4 (2019): p.

The interpretation of C1s XPS spectra from disordered oxygenated carbons remains uncertain despite a variety of schemes reported in the literature. Here, a thermoseries of cellulose chars was studied to evaluate six published deconvolution schemes; however, none were capable of correctly identifying the oxygen content determined by the O1s spectrum. To improve the self-consistency of the XPS interpretation a method is proposed based on a 7 peak C1s deconvolution, 3 C-C peaks, 3 oxygenated peaks, and pi-pi* transition peak. Deconvolution of the O1s by 4 peaks is used to determine O-C and O=C contributions which provide upper and lower bounds for the related C1s peaks: C-O, C=O and COO. To improve assignments, various functional groups and carbon structures have been examined via DFT using an initial state approximation. DFT calculations of model compounds (pyrene, cellobiose and peryelene tetracarboxylic dianhydride (PTCDA)) were compared with experimental results to confirm the validity of the calculation method used. The DFT calculations identified several defect structures that justify the use of 3 peaks for deconvolution of the C-C region of C1s XPS spectra. The deconvolution method proposed provides C:O ratios in good agreement (within 5 %) of those obtained from total C1s and O1s peaks.

Panchromatic observations of the best candidate HyLIRG from the widest Herschel extragalactic imaging survey have led to the discovery of at least four intrinsically luminous z = 2.41 galaxies across a ≈100-kpc region -a cluster of starbursting proto-ellipticals. Via sub-arcsecond interferometric imaging we have measured accurate gas and star-formation surface densities. The two brightest galaxies span ∼3 kpc FWHM in submm/radio continuum and CO J = 4−3, and double that in CO J = 1−0. The broad CO line is due partly to the multitude of constituent galaxies and partly to large rotational velocities in two counter-rotating gas disks -a scenario predicted to lead to the most intense starbursts, which will therefore come in pairs. The disks have M dyn of several ×10 11 M ⊙ , and gas fractions of ∼ 40%. Velocity dispersions are modest so the disks are unstable, potentially on scales commensurate with their radii: these galaxies are undergoing extreme bursts of star formation, not confined to their nuclei, at close to the Eddington limit. Their specific star-formation rates place them > ∼ 5× above the main sequence, which supposedly comprises large gas disks like these. Their high star-formation efficiencies are difficult to reconcile with a simple volumetric star-formation law. N-body and dark matter simulations suggest this system is the progenitor of a B(inary)-type ≈ 10 14.6 -M ⊙ cluster.

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