Research Students

  • Tim Lingard (ICG PhD exp. 2020) - Tim's Google Faculty Research Award funded PhD is focused on developing a novel interface for The Zooniverse which will allow in-browser fitting of galaxy light profiles.
  • Lucy Newnham (ICG PhD exp. 2019) - Lucy's PhD focuses on an interesting sample of very strongly barred *and* gas rich galaxies - something we found to be very ususual (Masters et al. 2012). Lucy has been obtaining resolved HI data for this sample, which we are calling the HIRBS (HI Rich Barred galaxy Survey).
  • Tom Melvin (ICG PhD 2016) - Tom's PhD used data from Galaxy Zoo: Hubble to study the redshift evolution of the bar fraction in spiral galaxies (Melvin et al. 2014). Tom now works as an Insurance Data Analyst.

Summary of Research Projects

  • SDSS-IV MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), is one of the five surveys which make up the Fourth phase of the Sloan Digital Sky Surveys (SDSS-IV). I've been part of MaNGA since the proposal stage, and recently have led on obtaining HI followup for the sample, using hundreds of hours of filler time at the Green Bank Telescope.
  • Galaxy Zoo - In much of my research I used Galaxy Zoo classifications to study the evolution of galaxies.
    • My first work with Galaxy Zoo involved studying the properties of the red spirals (BBC News Article about them) and also the general dust properties of spirals. Check out my Galaxy Zoo Blog Posting about this work. I led two papers on this in 2010, one on the dust (Masters et al. 2010a), the other on red spirals in general (Masters et al. 2010b; see below).
    • One of the interesting surprises about the red spirals was that they had unusually large numbers of bars. So I got interested in using Galaxy Zoo 2 data to study barred spirals. Galaxy Zoo bar classifications have since been used for numerous peer reviewed papers on bars in galaxies. Please read my blog post about the first paper (Masters et al. 2011a). This page has some example images of barred and unbarred galaxies in Galaxy Zoo (as does this page of 2000 examples; 200 in every 0.1 in pbar. We have also used a Google Sky Tool to measure the length of bars (published in Hoyle, Masters et al. 2011); studied correlations of the bars with environment (Skibba, Masters et al. 2011), and most recently looked at the correlation between bars and atomic gas content from ALFALFA (Masters et al. 2012). You can read more about this latest work in this blog article, and look at the galaxies in the sample here.
  • - I was a co-I on this economics/sociology project studying why people volunteer online. As part of this we also investigated how much people learn by participating in online citizen science, discovering that there is clear evidence for subject specific learning, and that citizen science projects act as an "engine of motivation" for science learning in general (Masters et al. 2016)
  • SDSS3 BOSS (Sloan Digital Sky Survey III, Baryon Acoustic Oscillation Sky Survey). I'm a member of the galaxy evolution working group, looking at the morphologies of BOSS targets in HST imaging (Masters et al. 2011b; see below), as well as figuring out how best to measure their sizes using SDSS images. (SDSS3 Description Paper, DR8 Data paper - I'm a co-author on both)
  • S4G (The Spitzer Survey of Structure in Galaxies) - I'm part of this successful Spitzer Warm Mission proposal to survey local galaxies. I was intially interested to use the data on inclined spirals to study the TF relation in the IR, and now I also plan an "S4GZoo". Stay tuned! (S4G Description paper)
  • ALFALFA (The Arecibo Legacy Fast ALFA Survey) - a blind HI survey ongoing at Arecibo. As a graduate student I helped with precurser observations for this large survey. I want to use the data to measure the dynamics of spiral galaxies for TF relation work, and also I'm interested in cross-correlating with Galaxy Zoo to study the gas content of spirals (both red and blue!).
  • ACSFCS (ACS Fornax Cluster Survey) - I have used data from this survey to study the correlations of the half-light radius of globular clusters in Fornax Cluster galaxies with other factors and investigating its use as a distance indicator. This work was published. ArXiV link
  • 2MRS (The 2MASS Redshift Survey) - the best all-sky redshift survey available. For my first postdoc at CfA I worked on obtaining complementary TF distances for a subset of the inclined spirals, and finishing of the redshift survey. 2MRS now published as Huchra et al. (2011). We announced the release of the data at the 218th AAS Meeting in Boston in May 2011, which got some press coverage. The data can be downloaded from the SAO/TDC.
  • 2MTF (The 2MASS Tully-Fisher Survey) - I initiated this survey during my first postdoc at CfA. It was aimed to be a matched TF survey for the 2MRS, with the most even sky coverage possible. We obtained over 400 hours of GBT observing time during my postdoc and observed 1000 galaxies to fill in the sky coverage. In addition we did a significant amount of observing at the Parkes telescope in Australia. To my delight, my Australian collaborators have continued working on this survey. Howlett et al. 2017 used it to measure the velocity power spectrum of the Universe.
  • SFI++ (Spiral Field I-band ++ Survey). This is the Tully-Fisher sample I worked on for my thesis. Currently the largest publicly available sample of measured peculiar velocities. It has been used to reconstruct the local gravity and estimate the bias between dark matter and galaxies. (Davis, Nusser, Masters, Springob, Huchra and Lemson, 2011). Download the data used to calibrated the TF relation in Masters et al. (2006) here.

Information about Selected Papers

Science Learning via Participation in Online Citizen Science, Masters et al. 2016, JCOM. In this work we discovered that a positive correlation between scientific content knowledge and active engagement in online citizen science projects. We interpreted this as citizen science acting as an "engine of motivation" for science learning.

Galaxy Zoo: an independent look at the evolution of the bar fraction over the last eight billion years from HST-COSMOS, Tom Melvin, Karen Masters et al. 2014 MNRAS 438, 2882. We used 2380 visually selected disc galaxies from the COSMOS survey to study the redshift evolution of the disc galaxy bar fraction. This formed a major part of Tom's PhD thesis.

Galaxy Zoo and ALFALFA: Atomic Gas and the Regulation of Star Formation in Barred Disc Galaxies, Karen Masters et al. 2012 MNRAS (in press; arXiV:1205.5271). We used 2090 galaxies with both morphologies from Galaxy Zoo and data on atomic hydrogen content from the ALFALFA survey at Arecibo to study the links between atomic gas content and whether or not a galaxy hosts a bar. We found a clear anti-correlation between atomic gas content and likelihood of hosting a bar. You can read more about this work in this blog article, and look at the galaxies in the sample here.

The Morphology of Galaxies in the Baryon Oscillation Spectroscopic Survey, Karen Masters et al. 2011 MNRAS 418, 1055 (arXiV:1106.3331). A look at the small fraction of the 1.5 millon intermediate redshift galaxies being observed by the SDSS3 project BOSS which have Hubble Space Telescope images (taken as part of the COSMOS project, which is the largest HST survey to date). We show that 75% are elliptical galaxies while the remaining 25% are massive disk galaxies. Images of all the galaxies in the sample can be viewed here. A blog post about the work appears on the SDSS3 blog.

Galaxy Zoo: Bar Lengths in Nearby Disc Galaxies, Ben Hoyle, Karen Masters, Bob Nichol et al. 2011, MNRAS.
The results of a Portsmouth based Galaxy Zoo offshoot project in which Ben Hoyle developed an interface using Google Sky in which volunteers could draw the shapes and sizes of bars on Galaxy Zoo galaxies. Our main finding is that bars in redder discs are longer and redder than those in bluer discs. MNRAS 415, 3627 ArXiV link. Ben's Galaxy Zoo blog post about it..

Galaxy Zoo: Morphological Classification and Citizen Science, Lucy Fortson, Karen Masters, Bob Nichol et al. 2011. Review article about Galaxy Zoo and the Zooinverse to appear in “Advances in Machine Learning and Data Mining for Astronomy” (edited by Michael Way, Jeff Scargle, Ashok Srivastava, and Kamal Ali). ArXiV link, and Lucy's Galaxy Zoo blog post about it.

Testing Gravity with Gas Rich Galaxies, Karen Masters and Kristine Spekkens, 2011
An invited viewpoint for PRL. Article link. We reviewed the paper: Novel Test of Modified Newtonian Dynamics with Gas Rich Galaxies by Stacy McGaugh. Stacy's work attracted some press. I blogged about our viewpoint and the other press at: "Beautiful Stars: Testing Gravity with Galaxies"

Galaxy Zoo: Bars in Disk Galaxies, Karen Masters et al. 2011, MNRAS
The first results from Galaxy Zoo 2 on trends of the bar fraction with other properties of disk galaxies. ( ArXiv link). See my blog post about this work and this page has some example images for this project. It was the subject of a RAS press release, and got covered in Nature Research Highlights, The Economist, Astronomy Now, A&G, WIRED and other places online like World Science.

Galaxy Zoo: Red Spirals, Karen Masters et al. 2010, MNRAS
A look at the intrinsically red spirals (as red as a normal elliptical) found in the Galaxy Zoo project. Link...

Galaxy Zoo: Dust in Spirals, Karen Masters et al. 2010, MNRAS
Looking at the impact of viewing angle on the colours of Galaxy Zoo spirals - which is interpreted as the effects of dust extinction in the disk. Link...

ACSFCS: Half-Light Radii of Globular Clusters in Early-Type Galaxies, Karen Masters et al. 2010, ApJ
An improved calibration of the use of globular cluster sizes as a distance indicator (and as a tracer of globular cluster evolution). This was work started as a Visiting Scientist at the Smithsonian Astrophysical Observatory with the help of funding from HST.
ArXiV link

The Tully-Fisher Relation in the Near Infra-Red, Karen Masters, John Huchra and Christopher Springob, 2008, ApJ
A new calibration of the universal Tully-Fisher (or luminosity--rotation speed) relation for spiral galaxies. I show the variation of the slope and zero-point with wavelength and spiral galaxy type.
Astroph link...
Download the data from this paper here.

Mapping Mass in the Local Universe
A conference proceedings paper describing the large TF survey I started during my first postdoc and summarizing the current best knowledge of the motions of galaxies in the local universe.
Astroph link...

SFI++ II: A New I-band Tully-Fisher Catalog, Derivation of Peculiar Velocities and Dataset Properties
The data release paper for the peculiar velocity sample I worked on for my thesis. Watch out for an upcoming erratum (minor corrections to a small percentage of the peculiar velocities)
Astroph link...

M81 by Galex, HST and Spitzer

My Publications:

  • My CV: pdf.
  • Download my PhD thesis: "Galaxy Flows in and Around the Local Supercluster" (Cornell, 2005) pdf (warning: large file!).