The Palomar Transient Factory (PTF) is a wide-field experiment designed to investigate the
optical transient and variable sky on time scales from minutes to years. PTF uses the CFH12k …

The Palomar Transient Factory (PTF) is a fully-automated, wide-field survey aimed at a
systematic exploration of the optical transient sky. The transient survey is performed using a new …

We present a comprehensive study to measure the locations of gamma-ray bursts (GRBs)
relative to their host galaxies. In total, we find the offsets of 20 long-duration GRBs from their …

Effective data visualization is a key part of the discovery process in the era of “big data”. It is
the bridge between the quantitative content of the data and human intuition, and thus an …

Quasars have long been known to be variable sources at all wavelengths. Their optical
variability is stochastic and can be due to a variety of physical mechanisms; it is also well-…

We have used WFPC2 to construct B, V color-magnitude diagrams of four metal-rich globular
clusters, NGC 104 (47 Tuc), NGC 5927, NGC 6388, and NGC 6441. All four clusters have …

We report the discovery of the first known probable case of a physical triple quasar. A
previously known double system, QQ 1429-008 at z= 2.076, is shown to contain a third, fainter …

We present a sample of 120 dust-reddened quasars identified by matching radio sources
detected at 1.4 GHz in the Faint Images of the Radio Sky at Twenty Centimeters survey with the …

We review the origins of the Virtual Observatory (VO) concept, and the current status of the
efforts in this field. VO is the response of the astronomical community to the challenges posed …

Sky surveys represent a fundamental data basis for astronomy. We use them to map in a
systematic way the universe and its constituents, and to discover new types of objects or …