The Sunyaev-Zel’dovich (SZ) effect is an important observational signature of galaxy clusters, the largest objects in the Universe today. In particular, the pairwise kinematic SZ signal probes the matter-velocity correlation function, scaled by the average optical depth of galaxy clusters, and is thus an interesting probe both from a cosmological and astrophysical point of view. […]

Recent all-sky transient searches have discovered new and unexpected explosion types that fall outside traditional SN classification schemes. These exotic outliers in many cases are due to the deaths of massive stars and therefore may have been prevalent in the primordial universe because the Pop III IMF is thought to be top-heavy. Depending on the […]

The first step toward construction of a hybrid optical detector like THEIA is the demonstration of separation of scintillation and Cherenkov light in liquid scintillators (LS). This would allow reconstruction of particle directionality in a low energy threshold detector, and provide improved particle identification. The CHESS experiment successfully images Cherenkov rings on LS such as […]

Prevailing models of antineutrino emission by nuclear reactors do not agree with observations. This discrepancy has been considered possible evidence for neutrino oscillation to non-interacting, or sterile, neutrino states. Although the existence of sterile neutrinos would have profound implications, a variety of measurements by the Daya Bay Experiment disfavor sterile models. I will summarize these […]

Adaptive optics correct for the blurring effects of the Earth’s atmosphere. However, most AO systems today suffer from limited fields of view and point spread functions that vary over time and position. I will present results from several experiments to overcome these limitations. We have deployed a ground-layer adaptive optics experiment on the UH 2.2 […]

The evidence for the existence of Dark Matter is well supported by many cosmological observations. But we have not yet been able to determine how this new type of matter fits into our understanding of the Universe on the smallest scales. Separately, long standing problems within the Standard Model point to new weakly interacting particles […]

The large-scale local bias parameters of dark matter halos are essential to describe the statistics of halos and galaxies on large scales, as well as for the halo model of the matter distribution. Using so-called separate universe simulations, we recently obtained precise measurements of the three leading bias parameters. For b2 and b3, these are […]

LIGO’s gravitational waves (GWs) detection has inaugurated an era to test the foundations of gravity. This includes also probing the nature of Dark Energy. Theories explaining the present acceleration of the Universe beyond the cosmological constant typically require adding extra gravitational degrees of freedom. This can lead to distinct signatures in the propagation of GWs. […]

Neutrinoless double beta (0νββ) decay is the only process which can feasibly investigate the Majorana nature of neutrinos and total lepton number conservation. A broad international experimental program requiring considerable resources is being mounted to search for 0νββ decay in the region of parameter space allowed for Inverted Ordering. The Bayesian discovery probability of future […]

In the era of precision cosmology, systematic uncertainty is quickly becoming the limiting factor in modern cosmological analyses. In my work, I discuss a method for performing supernova analyses by combining a hierarchical Bayesian framework with Monte-Carlo simulation realisations. This gains both the flexibility and speed of an analytic analysis along with the nuance and […]

The Milky Way's dust is of basic importance in astronomy. It is both crucial to the formation of stars and is a pervasive observational nuisance. Despite the dust's importance, existing dust maps are largely limited to two dimensions, with the distance to the dust unknown. The advent of large surveys like Pan-STARRS1 has allowed us […]

Over the past few years, clustering-based redshift estimation has emerged as a new way to estimate redshifts and perform extragalactic tomography of arbitrary datasets. On a similar timescale, observations by Planck, WISE, Pan-STARRS and 21cm radio surveys have been used to create a multitude of SFD-type Galactic dust maps. I will explain how clustering-based redshift […]

Neutron-star mergers and core-collapse supernovae are promising events to herald a new era of multi-messenger astronomy, as they release substantial amounts of energy in gravitational waves, neutrinos, and electromagnetic emission. Moreover, these events are connected to long-standing physics questions related to, e.g., heavy-element nucleosynthesis, gamma-ray bursts, and the nuclear equation of state. However, while offering […]

Cataloging is challenging in crowded fields because sources are extremely covariant with their neighbors and blending makes even the number of sources ambiguous. We present the first optical probabilistic stellar catalog, cataloging a crowded (~0.1 sources per pixel) Sloan Digital Sky Survey r band image from M2. Probabilistic cataloging returns an ensemble of catalogs inferred […]

Understanding the circumgalactic medium--the gaseous halo surrounding a galaxy, is an integral part to understanding galaxy evolution. The z ~ 2-3 universe is interesting as this is when the star formation rate and AGN activity peak. My work concludes the decade-long Quasars Probing Quasars survey designed for studying massive galaxy formation and quasar feedback. I […]

The line-of-sight power spectrum (P_F(k)) of the Ly-α forest has proven to be a valuable tool for doing cosmological observations. It also not only allows to constrain cosmological parameters, but enables us to measure the thermal state of the IGM at redshifts z>1.8. While at large scales (k<0.02 s/km) P_F(k) has been accurately measured using […]

Deep Learning has revolutionized the fields of computer vision, speech recognition and control systems. Can Deep Learning (DL) work for scientific problems? This talk will explore a variety of DOE/LBL applications that are currently benefiting from Deep Learning. We will review classification and regression problems in astronomy, cosmology, neuroscience, genomics and high-energy physics. We will […]

I will describe our development of a convolutional neural network (CNN) to learn to search for and characterize absorption lines in quasar spectra. Specifically, the algorithm discovers and measures the redshift and Hydrogen column density of damped Lya systems (DLAs). These systems dominate the neutral hydrogen gas of the universe, trace the interstellar medium of […]

In the last few years, the dark matter field has bifurcated into experiments focused on wimp-scale dark matter with massive liquid noble detectors and experiments focused on so-called ‘hidden sectors’ dark matter, pushing small detectors to much lower energy resolutions. Low-mass dark matter searches, focusing on single eV-scale energy deposits, are sensitive to different backgrounds […]