Related papers: H_2D^+: a light on baryonic dark matter?
We present a survey of the ortho-H2D+(1_{1,0}-1_{1,1}) line toward a sample of 10 starless cores and 6 protostellar cores, carried out at the Caltech Submillimeter Observatory. The high diagnostic power of this line is revealed for the…
Interstellar CO2 is an important reservoir of carbon and oxygen, and one of the major constituents of the icy mantles of dust grains, but it is not observable directly in the cold gas because has no permanent dipole moment. Its protonated…
We summarize recent attempts to detect warm ionized gas at large galactocentric distances. This includes searching for gas at the edges of spirals, in between cluster galaxies, towards extragalactic HI clouds, and towards high velocity…
The molecular gas content of high-redshift galaxies is a highly sought-after property. However, H$_2$ is not directly observable in most environments, so its mass is probed through other emission lines (e.g., CO, [CI], [CII]), or through a…
Using archival, high-resolution far-ultraviolet HST/STIS spectra of 34 Galactic O and B stars, we measure CI column densities and compare them with measurements from the literature of CO and H_2 with regard to understanding the presence of…
Dark matter particles populating our galactic halo could be directly detected by measuring their scattering off target nuclei or electrons in a suitable detector. As this interaction is expected to occur with very low probability and would…
Molecular hydrogen being unobservable in cold molecular clouds, the column density measurements of molecular gas currently rely either on dust emission observation in the far-IR or on star counting. (Sub-)millimeter observations of numerous…
Much of the baryonic matter in the Universe is in the form of H2 which includes most of the gas in galactic and extragalactic interstellar clouds. Molecular hydrogen plays a significant role in establishing the thermal balance in many…
ABRIDGED: Context: HI and CO large scale surveys of the Milky Way trace the diffuse atomic clouds and the dense shielded regions of molecular hydrogen clouds. However, until recently, we have not had spectrally resolved C+ surveys to…
The non-linear process of cosmic structure formation produces gravitationally bound overdensities of dark matter known as halos. The abundances, density profiles, ellipticities, and spins of these halos can be tied to the underlying…
Star formation activity in molecular clouds is often found to be correlated with the amount of material above a column density threshold of $\sim 10^{22} \, {\rm cm^{-2}}$. Attempts to connect this column density threshold to a ${\it…
The nature of the dark matter in the Universe is one of the outstanding questions in astrophysics. In this talk, I address possible stellar baryonic contributions to the 50-90% of our Galaxy that is made of unknown dark matter. First I show…
Interstellar dark clouds are the sites of star formation. Their main component, dihydrogen, exists under two states, ortho and para. H2 is supposed to form in the ortho:para ratio (OPR) of 3:1 and to subsequently decay to almost pure…
The Lambda Cold Dark Matter (LCDM) paradigm makes specific predictions for the abundance, structure, substructure and clustering of dark matter halos, the sites of galaxy formation. These predictions can be directly tested, in the low-mass…
We present sensitive, high angular resolution molecular-line observations of C18O and N2H+ toward the dark globule B68. We directly compare these data with the near-infrared extinction measurements of Alves, Lada, & Lada (2001) to derive…
While it is possible to estimate the dark matter density at the Sun distance from the galactic center, this does not give information on actual dark matter density in the Solar system. There can be considerable local enhancement of dark…
We present the first results of the Herschel open time key program, Galactic Observations of Terahertz C$^+$ (GOT C+) survey of the [CII] fine-structure line at 1.9 THz (158 microns) using the HIFI instrument on Herschel. We detected 146…
We have detected new HD absorption systems at high redshifts, z_abs=2.626 and z_abs=1.777, identified in the spectra of the quasars J0812+3208 and Q1331+170, respectively. Each of these systems consists of two subsystems. The HD column…
We investigate the atomic (HI) and molecular (H_2) Hydrogen content of normal galaxies by combining observational studies linking galaxy stellar and gas budgets to their host dark matter (DM) properties, with a physically grounded galaxy…
Transmission spectroscopy of exoplanets has the potential to provide precise measurements of atmospheric chemical abundances, in particular of hot Jupiters whose large sizes and high temperatures make them conducive to such observations. To…