Spatially Resolved Galactic Wind in Lensed Galaxy RCSGA 032727-132609

We probe the spatial distribution of outflowing gas along four lines of sight separated by up to 6 kpc in a gravitationally-lensed star-forming galaxy at z=1.70. Using MgII and FeII emission and absorption as tracers, we find that the clumps of star formation are driving galactic outflows with velocities of -170 to -250 km/sec. The velocities of MgII emission are redshifted with respect to the systemic velocities of the galaxy, consistent with being back-scattered. By contrast, the FeII fluorescent emission lines are either slightly blueshifted or at the systemic velocity of the galaxy. Taken together, the velocity structure of the MgII and FeII emission is consistent with arising through scattering in galactic winds. Assuming a thin shell geometry for the out owing gas, the estimated masses carried out by these outfows are large (> 30 - 50 $\rm{M_{\odot} yr^{-1}}$), with mass loading factors several times the star-formation rate. Almost 20% to 50% of the blueshifted absorption probably escapes the gravitational potential of the galaxy. In this galaxy, the outflow is "locally sourced", that is, the properties of the outflow in each line of sight are dominated by the properties of the nearest clump of star formation; the wind is not global to the galaxy. The mass outflow rates and the momentum flux carried out by outflows in individual star forming knots of this object are comparable to that of starburst galaxies in the local Universe.Comment: 19 pages, 10 figure, accepted for publication in MNRA

Leptonic decay of Heavy-light Mesons in a QCD Potential Model

We study the masses and decay constants of heavy-light flavour mesons D, Ds, B and Bs in a QCD Potential model. The mesonic wavefunction is used to compute the masses of D and B mesons in the ground state and the wavefunction is transformed to momentum space to estimate the pseudoscalar decay constants of these mesons. The leptonic decay widths and branching ratio of these mesons for different leptonic channels are also computed to compare with the experimental values. The results are found to be compatible with available data.Comment: 9 pages,3 table

On The Nature of Ring Patterns In Ice Crystals of Hailstones: A Signature of Global Warming

In the present work we report for the first time the ring patterns in the ice crystals procured from hailstones at Doom Dooma (27.40N, 95.30E) on March 17, 2016 and April 9, 2017. We have measured the intensity patterns of the rings with the help of a software (ImageJ). Since the ring patterns have been observed in the ice crystals of hailstones only in recent years, it is reasonable to believe that they will give valuable information on the process of ice nucleation and possibly on global warming

Spatially Resolved Patchy Lyman-α\alpha Emission Within the Central Kiloparsec of a Strongly Lensed Quasar Host Galaxy at z = 2.8

We report the detection of extended Lyman-$\alpha$ emission from the host galaxy of SDSS~J2222+2745, a strongly lensed quasar at $z = 2.8$. Spectroscopic follow-up clearly reveals extended Lyman-$\alpha$ in emission between two images of the central active galactic nucleus (AGN). We reconstruct the lensed quasar host galaxy in the source plane by applying a strong lens model to HST imaging, and resolve spatial scales as small as $\sim$200 parsecs. In the source plane we recover the host galaxy morphology to within a few hundred parsecs of the central AGN, and map the extended Lyman-$\alpha$ emission to its physical origin on one side of the host galaxy at radii $\sim$0.5-2 kpc from the central AGN. There are clear morphological differences between the Lyman-$\alpha$ and rest-frame ultraviolet stellar continuum emission from the quasar host galaxy. Furthermore, the relative velocity profiles of quasar Lyman-$\alpha$, host galaxy Lyman-$\alpha$, and metal lines in outflowing gas reveal differences in the absorbing material affecting the AGN and host galaxy. These data indicate the presence of patchy local intervening gas in front of the central quasar and its host galaxy. This interpretation is consistent with the central luminous quasar being obscured across a substantial fraction of its surrounding solid angle, resulting in strong anisotropy in the exposure of the host galaxy to ionizing radiation from the AGN. This work demonstrates the power of strong lensing-assisted studies to probe spatial scales that are currently inaccessible by other means.Comment: Accepted to ApJ Letters; 7 pages, 5 figure

Investigating MgII Absorption in Paired Quasar Sight-Lines

We test whether the Tinker & Chen model of MgII absorption due to the gaseous halo around a galaxy can reproduce absorption in quasar pairs (both lensed and physical) and lensed triples and quads from the literature. These quasars exhibit absorption from a total of 38 MgII systems spanning z=0.043 - 2.066 with mean redshift =1.099 and weighted mean rest-frame equivalent width of 0.87 Ang. Using the Tinker & Chen model to generate simulated sight-lines, we marginalize the unknown parameters of the absorbing galaxies: dark matter halo mass, impact parameter, and azimuthal angle on the sky. We determine the ability of the model to statistically reproduce the observed variation in MgII absorption strength between paired sight-lines for different values of the gas covering fraction f_c and the characteristic length scale ell_c, within which the variation in absorption equivalent widths between sight-lines exponentially decreases. We find a best-fit f_c=0.60 \pm 0.15 and ell_c<8/h_70 kpc (1\sigma confidence limits), with smaller f_c allowed at larger ell_c. At 99.7% confidence, we are able to rule out f_c>0.87 for all values of ell_c and the region where ell_c<1.0/h_70 kpc and f_c<0.3.Comment: 24 pages, 11 figures, 2 tables, accepted for publication in MNRAS, 1 Dec 201

The Properties of the Circumgalactic Medium in Red and Blue Galaxies: Results from the COS-GASS+COS-HALOS Surveys

We use the combined data from the COS-GASS and COS-Halos surveys to characterize the Circum-Galactic Medium (CGM) surrounding typical low-redshift galaxies in the mass range ${M}_{* }\sim \,{10}^{9.5-11.5}\,{M}_{\odot }$, and over a range of impact parameters extending to just beyond the halo virial radius (R vir). We find the radial scale length of the distributions of the equivalent widths of the Lyα and Si iii absorbers to be ~1 and ~0.4 R vir, respectively. The radial distribution of equivalent widths is relatively uniform for the blue galaxies, but highly patchy (i.e., it has a low covering fraction) for the red galaxies. We also find that the Lyα and Si iii equivalent widths show significant positive correlations with the specific star formation rate (sSFR) of the galaxy. We find a surprising lack of correlations between the halo mass (virial velocity) and either the velocity dispersions or velocity offsets of the Lyα lines. The ratio of the velocity offset to the velocity dispersion for the Lyα absorbers has a mean value of ~4, suggesting that a given line of sight is intersecting a dynamically coherent structure in the CGM, rather than a sea of orbiting clouds. The kinematic properties of the CGM are similar in the blue and red galaxies, although we find that a significantly larger fraction of the blue galaxies have large Lyα velocity offsets (>200 km s−1). We show that—if the CGM clouds represent future fuel for star formation—our new results could imply a large drop in the sSFR across the galaxy mass-range we probe

The COS Absorption Survey of Baryon Harbors (CASBaH): Warm-hot Circumgalactic Gas Reservoirs Traced by Ne VIII Absorption

We survey the highly ionized circumgalactic media (CGM) of 29 blindly selected galaxies at 0.49 < z_(gal) < 1.44 based on high-S/N ultraviolet spectra of z > 1 QSOs and the galaxy database from the COS Absorption Survey of Baryon Harbors (CASBaH). We detect the Ne VIII doublet in nine of the galaxies, and for gas with N(Ne VIII) > 10^13.3 cm^-2 (> 10^13.5 cm^-2), we derive a Ne VIII covering fraction f_c = 75 +15/-25% (44 +22/-20%) within impact parameter (rho) < 200 kpc of M_* = 10^(9.5-11.5) Msol galaxies and f_c = 70 +16/-22% (f_c = 42 +20/-17%) within rho < 1.5 virial radii. We estimate the mass in Ne VIII-traced gas to be M_gas(Ne VIII) > 10^9.5 Msol (Z/Zsol)^-1, or 6-20% of the expected baryonic mass if the Ne VIII absorbers have solar metallicity. Ionizing Ne VII to Ne VIII requires 207 eV, and photons with this energy are scarce in the CGM. However, for the median halo mass and redshift of our sample, the virial temperature is close to the peak temperature for the Ne VIII ion, and the Ne VIII-bearing gas is plausibly collisionally ionized near this temperature. Moreover, we find that photoionized Ne VIII requires cool and low-density clouds that would be highly underpressured (by approximately two orders of magnitude) relative to the putative, ambient virialized medium, complicating scenarios where such clouds could survive. Thus, more complex (e.g., non-equilibrium) models may be required; this first statistical sample of Ne VIII absorber/galaxy systems will provide stringent constraints for future CGM studies.Comment: Published in ApJL, Volume 877, Issue 2, Article L2