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We present a systematic study of deuterated molecular hydrogen (HD) at high redshift, detected in absorption in the spectra of quasars. We present four new identifications of HD lines associated with known $rm H_2$-bearing Damped Lyman-$alpha$ systems. In addition, we measure upper limits on the $rm HD$ column density in twelve recently identified $rm H_2$-bearing DLAs. We find that the new $rm HD$ detections have similar $N({rm HD})/N(rm H_2)$ ratios as previously found, further strengthening a marked difference with measurements through the Galaxy. This is likely due to differences in physical conditions and metallicity between the local and the high-redshift interstellar media. Using the measured $N({rm HD})/N({rm H_2})$ ratios together with priors on the UV flux ($chi$) and number densities ($n$), obtained from analysis of $rm H_2$ and associated CI lines, we are able to constrain the cosmic-ray ionization rate (CRIR, $zeta$) for the new $rm HD$ detections and for eight known HD-bearing systems where priors on $n$ and $chi$ are available. We find significant dispersion in $zeta$, from a few $times 10^{-18}$ s$^{-1}$ to a few $times 10^{-15}$ s$^{-1}$. We also find that $zeta$ strongly correlates with $chi$ -- showing almost quadratic dependence, slightly correlates with $Z$, and does not correlate with $n$, which probably reflects a physical connection between cosmic rays and star-forming regions.
We report cosmic ray ionization rates towards ten reddened stars studied within the framework of the EDIBLES (ESO Diffuse Interstellar Bands Large Exploration Survey) program, using the VLT-UVES. For each sightline, between 2 and 10 individual rotati
ALMA observations of the long wavelength dust continuum are used to estimate the interstellar medium (ISM) masses in a sample of 708 galaxies at z = 0.3 to 4.5 in the COSMOS field. The galaxy sample has known far-infrared luminosities and, hence, sta
We present deep high resolution (0.03, 200pc) ALMA Band 7 observations covering the dust continuum and [CII] $lambda157.7mu$m emission in four $zsim4.4-4.8$ sub-millimeter galaxies (SMGs) selected from the ALESS and AS2UDS surveys. The data show that
Using the Cosmic Origins Spectrograph aboard the Hubble Space Telescope, we measured the abundances of six ions (C III, C IV, Si III, Si IV, N V, O VI) in the low-redshift (z < 0.4) intergalactic medium and explored C and Si ionization corrections fr
Using three-dimensional magnetohydrodynamics simulations, we show that the efficiency of cosmic-ray (CR) production at supernova remnants (SNRs) is over-predicted if it could be estimated based on proper motion measurements of H$alpha$ filaments in c