Introducing Richard Easther

Prof Richard Easther is an astrophysicist at the University of Auckland, in New Zealand. Easther’s work spans topics in astrophysics and particle cosmology. These range from the behaviour of dark matter on galactic scales, through to the cosmology of the “multiverse”, observational signatures of the hypothetical “inflationary” era, and the possible cosmological implications of string theory.

Easther is a New Zealander, and completed his undergraduate degree and PhD at the University of Canterbury in Christchurch, New Zealand, graduating with his doctorate in 1994. He held post-doctoral positions at Waseda in Tokyo, Brown in Providence. Rhode Island, and Columbia in New York City. Easther became a faculty member in Physics and Astronomy at Yale University from 2004. He returned to New Zealand at the end of 2011, moving home to take up a professorship at the University of Auckland, where he is currently Head of Department [Chair] of Physics.

An enthusiastic teacher, Easther has led a major overhaul of the undergraduate physics curriculum at the University of Auckland, and he is a co-founder of the university’s Science Scholars programme. Easther has been involved with a number of initiatives to improve equity outcomes, and he is a frequent commentator on science and technology issues in New Zealand. His blog is at, he is on twitter at @reasther and his group’s homepage is at


Introducing Héctor Vives-Arias

Héctor Vives-Arias (@DarkSapiens) obtained his PhD in Physics at the University of Valencia, Spain, using gravitational lenses to study both the structure of quasars and the distribution of dark matter subhaloes. He is currently a postdoc at the Instituto de Astrofísica de Canarias (IAC), where he works with ALMA observations of the active galactic nucleus in NGC 1068 to try to understand the structure and kinematics of the dust and molecular gas surrounding its center.
In his last year as an undergrad he got a summer grant at the IAC, where he analyzed the distribution and velocity of the gas in several nearby active galactic nuclei by working with near infrared integral field spectroscopy data from the SINFONI instrument at the VLT. For his Master’s thesis in Valencia, however, he switched to gravitational lens systems in which quasars were multiply imaged by foreground galaxies. Continuing this work on this PhD thesis, he used observations of the Einstein Cross in the optical and mid infrared (from the CanariCam instrument at the Gran Telescopio Canarias) to determine the size and temperature profile of the accretion disk of the quasar by studying the gravitational microlensing in the system, and also to estimate the amount of substructure in the dark matter halo of the lens galaxy that would produce the non-microlensed flux ratios between the quasar images. He also stayed for about a year at the University of Manchester, where he learned to work with radio interferometry data. There, he processed VLA observations of another lens system in order to measure the flux ratios between the multiple images, and to also determine the size of the radio emitting region.
He is currently working on a study of a dozen quadruply lensed systems to estimate the abundance of dark matter subhaloes from the flux ratios between the quasar images in observations of their narrow line regions, radio cores, and dusty tori, while also analyzing ALMA data of nearby active galactic nuclei to study those dusty tori directly in his recently started postdoc at the IAC.
Despite his research focus on active galaxies and dark matter, his scientific interests are much broader than that, and he always tries to keep learning as much as he can about many different fields. He has a passion for science communication that has helped him remain motivated in the low moments of academic life, and he regularly enjoys explaining science on Twitter, blog articles, radio programs, podcasts, and public talks. Other hobbies include archery, drawing, and 3D animation and rendering.

Introducing Jay Strader

Jay is an assistant professor in the Department of Physics and Astronomy at Michigan State University. Recently his research has centered around compact binaries in the Milky Way, especially searches for accreting black holes in globular clusters. His interests also include the distribution of dark matter around galaxies, the formation of stellar halos, and the initial mass function of stars in massive star clusters.
From 2007-2012 he was a Hubble Fellow and Menzel Fellow at the Harvard-Smithsonian Center for Astrophysics. He earned his BS in Physics and Mathematics at Duke University, and his PhD at the University of California-Santa Cruz. As his Twitter biography says (@caprastro), he loves “goats, birds, the Celtics, and globular clusters”.

Introducing Demitri Muna

I am excited to be hosting week two (19-25 Jan 2014) of Astrotweeps! I am an astrophysicist who works on the Sloan Digital Sky Survey (SDSS) at Ohio State University. SDSS was responsible for producing the largest color image of the sky ever made – a trillion pixels that would require half a million HDTVs to display. But that’s old news – the current phase of the survey has collected over a million spectra of stars and galaxies. A spectrum is a measurement where the light is split into different wavelengths, like that you would see through a prism. My current research interest is using this data to learn how galaxies evolve over time and even the histories of individual galaxies. I am also interested in the data science aspect of research; how we as astronomers can analyze and do science with far more data than we’ve ever had access to. It’s a good problem to have, but not a solved one. I’m also a contributor to the Astropy project. I am also interested in public outreach and run a chapter of Astronomy On Tap. In a prior life, I worked on a dark matter experiment called DRIFT, located 1.1km underground in a working mine that is a stone’s throw from where Dracula landed in England. I also curl.

I look forward to your questions on galaxy evolution, dark matter, curling, or anything else you’d like to hear about! Send questions to @astrotweeps or as a comment on this blog post. After this week, you can follow me on Twitter at @demitrimuna and @scicoder.