2017 Collaboration Meeting in Santiago, Chile

The scientists who are part of the Sloan Digital Sky Surveys gather once a year for a collaboration meeting. One of the themes of this meeting is looking for synergy and collaboration across the different surveys, and institutions which are part of SDSS.

For 2017 the meeting happened July 24-26th 2017 on the beautiful Campus San Joaquin of Pontifica Universidad de Catolica in Santiago, Chile, hosted by the Chilean Participation Group of SDSS (a collaboration of seven different Chilean Universities).

SDSS Collaboration Members attending SDSS2017. Around 120 scientists from all over the collaboration attended the meeting. The plates shown are APOGEE-2S plates brought down specially from Las Campanas.

Congratulations to the APOGEE Instrument Team

Everyone at SDSS-IV wishes to congratulate the APOGEE instrument team, and especially John Wilson for being announced as the 2017 winners of the Maria and Eric Muhlmann Award of the Astronomical Society of the Pacific.

John Wilson celebrates first light for the APOGEE-S instrument. Credit: SDSS.

The award citation reads:

The Maria and Eric Muhlmann Award recognizes significant observational results made possible by innovative advances in astronomical instrumentation, software, or observational infrastructure. The 2017 recipient of the Muhlmann Award is Dr. John Wilson (University of Virginia) and the APOGEE team for the design, construction, and commissioning of the APOGEE instrument located at the Apache Point Observatory in New Mexico – the linchpin of the APOGEE surveys that have been a part of the Sloan Digital Sky Survey III (SDSS-III) and Sloan Digital Sky Survey IV (SDSS-IV).

APOGEE (Apache Point Observatory Galactic Evolution Experiment) is a groundbreaking, high-resolution, near-infrared, spectrographic survey of red giant stars in the Milky Way Galaxy. By observing near-infrared light, the custom built APOGEE instrument can efficiently see through most of the obscuring dust to study the galactic bulge, disc, and halo. Collecting spectra from 300 targets simultaneously, APOGEE is responsible for the world’s largest high-resolution, near-infrared spectroscopic survey of stars in our Galaxy. After six years of operation, APOGEE has collected data on over 250,000 stars.

As one of the nominators stated, the APOGEE instrument “produced scientifically viable data the moment it was deployed onto the sky and functioned far better than anyone expected.” The instrument was so successful that a copy has been fabricated, installed, and started operating at the 2.5-meter du Pont Telescope at Las Campanas Observatory in Northern Chile. This instrument, in a Southern Hemisphere location, together with the first instrument, provides the APOGEE Survey access to the entire Milky Way.

The award will be officially given at an Awards Gala on October 28, 2017.

Congratulations to John and the entire instrument team from all of us, and here’s to many years of APOGEE data to come from two hemispheres!

The APOGEE team in front of the instrument after it was delivered and installed in the instrument room at Las Campanas Observatory. Kneeling, from left: Garrett Ebelke, John Wilson, Jimmy Davidson. Middle: Matt Hall, Mita Tembe, Fred Hearty, Juan David Trujillo. Back: Nick MacDonald.

Spotlight on APOGEE: Engineering with Garrett Ebelke

Garrett Ebelke (center), with his wife, Stefanie, and their daughter, Madeleine

We have featured the building and delivery of APOGEE-2 several times before (like here, here, and here), so you may recognize the person we are spotlighting today. Garrett grew up in Kansas, but took an early interest in triathlons that brought him to the University of Colorado at Boulder, with all of its lovely mountains, for college. While there, he majored in astronomy. He took a class in observational astronomy that sparked his interest in working with telescopes. So after graduation, when a position as a Telescope Technologist on the 2.5-m SDSS telescope at Apache Point Observatory opened up, he jumped on it…and has been associated with SDSS ever since.

When APOGEE-1 arrived to Apache Point Observatory in 2011, Garrett was working the day shift as a fiber optics technician. His job was to plug plates for each night’s observations. As the telescope shut down for regular summer maintenance, he was asked to support the installation of APOGEE-1. This was the first time that Garrett was exposed to the engineering side of astronomy, and he says that he “was very intrigued”. Below is a picture of Garrett in the clean room with APOGEE-1, along with Principal Investigator Steve Majewski, Instrument Scientist John Wilson, and project scientist Gail Zasowski.

From left to right: Garrett Ebelke, Gail Zasowski, Steve Majewski (reflected), and John Wilson, standing together in the clean room with the APOGEE-1 instrument.

After 18 months at APO, Garrett transitioned to a job as a Telescope Operations Specialist, in which he was up at night running the observations of the SDSS telescope. He used this opportunity to begin taking engineering courses during the daylight hours, so that he could build a better background for instrumentation in astronomy. After several years (and several courses), he was approached about taking place in a unique opportunity: building APOGEE-South. In Garrett’s words: “Since I had seen both the day time plugging and night time operations, I was uniquely qualified to train the Chilean observers/pluggers. Shortly after, I began to design the Plugging and Mapping station with [Chief Engineer] French Leger. As I was handing this design off to French to finalize and fabricate, my wife Stefanie gave birth to our first daughter, Madeleine, and two weeks later, we relocated to Charlottesville, Virginia, so I could become involved in building the APOGEE-South instrument.” Talk about a busy two weeks.

From all accounts Garrett has stayed busy in Virginia ever since. It would take too long to explain everything that he has done to assist with the construction of APOGEE-South; suffice it to say that the end product, safely delivered and installed at Las Campanas Observatory, is a testament to his and many others’ hard work — see the team photo below. He has additionally assisted with upgrades at the University of Virginia’s Fan Mountain Observatory, and is in graduate school at Iowa State University pursuing a Master’s degree in Mechanical Engineering. Garrett says that his graduate coursework has been hugely beneficial to his work with APOGEE, and his impact on the team has been equally so.

The APOGEE team in front of the instrument after it was delivered and installed in the instrument room at Las Campanas Observatory. Kneeling, from left: Garrett Ebelke, John Wilson, Jimmy Davidson. Middle: Matt Hall, Mita Tembe, Fred Hearty, Juan David Trujillo. Back: Nick MacDonald.

Where there’s a data release, there’s documentation!

Last week, more than a dozen SDSS IV-midables gathered in St Andrews, Scotland for a very important task: preparing the documentation for the Fourteenth SDSS Data Release.  This information — from high-level overviews of the surveys to column-by-column description of the files — is one of the reasons SDSS is the most highly cited dataset in the history of astronomy.  (Too strong?  No, it’s actually true: Madrid & Macchetto 2006, 2009.)

The APOGEE-2 Team love documenting – Gail Zasowksi succeeds in breaking Jen Sobeck’s concentration.

SDSS holds one of these documentation workshops for every data release: e.g., DocuFeest (DR13), DocuLuau (DR12), DocuGras (DR10), and DocuFiesta (DR9).  As the DR14 incarnation was being held in Scotland, it was dubbed the DocuCeilidh — “Ceilidh” is a Gaelic term for an evening full of traditional music, dancing, and storytelling.

The MaNGA documentation team (plus Bonnie) lay out their plans for the week.

Over four days, the DR14 DocuCeilidh team added or updated 180 webpages and rewrote more than 50 data models.  There were 12 operating Slack channels, meters of emails, and almost non-stop discussion across the tables, even as people ducked in and out of the room to sit on numerous telecons and other meetings.

More evidence of the team hard at work documenting SDSS-IV data.

Rita Tojeiro and Johan Comparat took charge of updating the information for eBOSS, which is releasing its first data in DR14.  MaNGA’s updates were overseen by Kyle Westfall, Amy Jones, David Stark, David Law, and Anne-Marie Weijmans.  In addition, José Sánchez-Gallego, Brian Cherinka, Sofia Meneses-Goytia, and Renbin Yan (joining remotely) made some advance preparations for MaNGA’s DR15 data products.  For its very first data release, APOGEE-2 was represented by Jen Sobeck and Gail Zasowski, with Jon Holtzman in close email contact (even outside of reasonable working hours…).

Jordan Raddick, Bonnie Souter, and Joel Brownstein (joining remotely) were kept busy answering technical questions, keeping a schedule, and making sure everyone had a functional platform in which to work.  SDSS-IV Spokesperson Karen Masters made great progress on the DR14 release paper, and also started adding credit lines to all images on the data release site, in advance of switching to a Creative Commons Attribution license for all SDSS images.  And Anne-Marie — in addition to the MaNGA documentation — kept a masterful hand on the organizational details and provided a steady stream of delicious treats to keep everyone fueled.

When docuCeilidhing we recommend you eat shortbread.

But even among the many, many person-hours of work put in (over 400, through the week), the Sloanies (of course) found a way to have a good time.  They explored St Andrews’ castle and cathedral ruins, sampled a wide range of Scottish whiskies, and attended a classical concert starring SDSS’s own Dr. Weijmans.  They even engaged in an exhilarating spot of ceilidh dancing, and spent a morning spying on some of the 46,200 nesting pairs of puffins on an island in the Firth of Forth.

Some of the team too a break to climb the St Rule’s Tower in St Andrews Cathedral.

A more traditional Ceilidh. Spot the SDSS-IV team members….

More evidence of dancing.

Walking for science on the Isle of May. We saw some Puffins. We went home happy.

DR14 is scheduled for July 31, and while there’s still some work to do before we deliver our latest product to the world, the DocuCeilidh accomplished quite a bit of the legwork for it to be a success.  In the meantime, plans are already in the works for the DR15 DocuTBD…stay tuned!

This post was written by Gail Zasowski.

SDSS-IV commitment to inclusivity

The below statement was shared with the SDSS-IV collaboration on 13th November. Following a request we now post it publicly here.


We write to affirm our commitment to treat every member of our collaboration with respect and dignity, regardless of their race, ethnicity, age, color, disability, faith, national origin, gender identity, gender expression, sexual orientation, social class, or political beliefs.

This week’s U.S. election results followed a long and divisive 2016 campaign. Our SDSS-IV collaboration is broad and international, and has a significant fraction of members based in the U.S. Our community comes from a range of backgrounds and experiences that may influence how they are impacted by current events.  We urge all members of the collaboration to be mindful of how we treat other members of our community during this challenging time.

We write particularly to express our solidarity with colleagues who have legitimate fears for their safety in the coming months and years. In the days following the election, some of us at U.S. institutions
have heard first-hand reports of harassment and intimidation of our colleagues and students, in some cases based on their race, of a sort that has previously been rare, and by perpetrators who expressed
political motivations.  Whatever one’s philosophy of government or beliefs about what economic, social, and foreign policies are best for the U.S., it is important that we reject such behavior; we hope that all of the U.S. national leaders will do so.

In this environment, we feel the need now to emphasize that in SDSS-IV we are committed to fostering an astronomy community that is safe, welcoming, and inclusive of all people, including those in historically marginalized groups.
SDSS-IV is currently in the process of drafting our Code of Conduct. Collaboration members are invited to comment on the current draft (link is internal website)  by emailing Jennifer Johnson (the Chair of the Code of Conduct Committee). You are also welcome to send comments to the Committee on Inclusiveness in SDSS (coins@sdss.org).

In the meantime please bring any concerns you have about collaboration climate to the collaboration management, or to our Ombudspeople, Jill Knapp and David Weinberg who can be contacted directly and confidentially via ombuds@sdss.org.

SDSS Collaboration Meeting 2016: Madison, Wisconsin, USA

At the end of June 2016, over 150 members of the SDSS collaboration met for workshops, talks, discussions, and fun by the lake at the University of Wisconsin, Madison. The week began with a two-day APOGEE workshop on Saturday and Sunday. On Sunday, the APOGEEans were joined in Madison by the FAST/REU bootcamp and the Plate workshop for teachers and scientists.

2016 SDSS collaboration meeting photograph. The happy attendees gathered by the beautiful lake. If you were there and not in this picture, you were probably getting coffee.

2016 SDSS collaboration meeting photograph. The happy attendees gathered by the beautiful lake. If you were there and not in this picture, you were probably getting coffee.

The FAST/REU students were getting up to speed really quickly on how to work with our data. The REU students are undergraduates who will be working on a science project over the summer, while the FAST students are graduate students in longer term teams with SDSS as we seek to help raise the participation of under-represented minorities.

On Monday-Wednesday, the meeting focused on discussions of SDSS-IV science, including many exciting results from the MaNGA survey, which is releasing its first data in Data Release 13. The APOGEE-2 survey present maps of the composition of stars across the Galaxy, characterizing the trends with position. The eBOSS survey showed the first results for large-scale structure of the Universe based on the 2014-2016 observations (very fast turn-around!). Quasars were also a big topic of conversation, as SDSS is now studying their evolution in detail. We are interested both in how they change over a few years time and mapping how they “grow” the supermassive black holes over billions of years. Results discussed that have been highlighted by SDSS in press releases/blog posts include the shutting off of star formation in galaxies by Edmond Cheng , additional examples of “changing look quasars” by Jessie Runnoe and the discovery that brown dwarfs could be quite common around certain types of stars by Nick Troup.

Poster for Daniel Eisenstein's public talk

Poster for Daniel Eisenstein’s public talk

We saw ways that other galaxies could “quench” their star formation in the presentation by Francesco Belfiore and could study the history of star formation in our Galaxy thanks to age maps by Melissa Ness. Apparently our galaxy has some similarities to other spiral galaxies! We tweeted a whole bunch about about the science results and will Storify some of our most popular tweets soon.

On Tuesday night, we had the collaboration meeting banquet, where we honored Dan Long, longtime Sloanie who worked at Apache Point Observatory for over 20 years, including as Chief Telescope Engineer for the Sloan Foundation Telescope. He is retiring next year and, as the email from Jim Gunn put it, “we will miss him more than I can say.” In addition to spoken tributes, we also showed of a movie of some of Dan’s greatest hits and well-wishes from the many other Sloanies. We will be posting that to youtube soon, so stay tuned.

The SDSS collaboration is big and includes people from many career stages, institutions, and cultures. We take the opportunity of these meetings to discuss how the collaboration is working and what we can do better. There was a thoughtful and thought-provoking discussion of how to improve the climate in SDSS and how to establish a “Code of Conduct” that will work to ensure that all are treated with respect.

This meeting also featured our first public talk by Daniel Eisenstein, talking about using the disturbances that sound waves left in the gas of the early Universe to trace the shape, past, and future of the Universe. He’s been working with SDSS data on this subject for over 10 years, so is a leading expert in this amazing result. The April 2016 edition of Sky and Telescope featured the article “Mapping the Universe’s Ancient Sound Waves” written by Daniel. The “Beyond the Pages” addition by the editors is also wonderful.

We had our most ambitious meeting ever for education and public outreach. The Plate Workshop on how to use an SDSS plate to introduce your class to the science of SDSS had a number of educators from across the US attending, looking pretty happy when they got their picture taken.

Educators from the Plate Workshop, organized by Kate Meredith (bottom right) and Karen Masters (who is probably taking the picture)

Educators from the Plate Workshop, organized by Kate Meredith (bottom right) and Karen Masters (who is probably taking the picture)

The Sunday workshop was followed on Monday and Tuesday by educators attending science talks, working with SDSS scientists on education and public outreach ideas, and doing an “EPO Hack Day” to create new activities for Voyages, SDSS’s website for how to use our data for education for K-12 students.

Thanks to the University of Wisconsin, especially the head of the Local Organizing Committee, Christy Tremonti, for hosting such a lovely meeting and we look forward to seeing everyone at the next meeting next summer.

SDSS Celebrates Leaders Inducted into the National Academy of Sciences

This year, we are pleased that two scientists related to the SDSS collaboration have been recognized for their wide contributions to astronomical research.

Professor Meg Urry, of Yale University, has served on the Advisory Committee for SDSS-III and SDSS-IV. Her research focuses of supermassive black holes, and she is known, among other things, for her work that demonstrates Active Galactic Nuclei are a common phase in galaxy evolution.

Dr. Meg Urry of Yale University

Dr. Meg Urry of Yale University

Professor Timothy Heckman, of John Hopkins University, has also served on the Advisory Committee for SDSS, as well as being an Astrophysical Research Consortium Board member from 1995 to 2000. His research touches upon the ways that supermassive black holes effect their host galaxies.

Dr. Timothy Heckman, Johns Hopkins University

Dr. Timothy Heckman, Johns Hopkins University

Congratulations to both Timothy and Meg on their achievements!

Tweep of the Week: Audrey Oravetz

This week our @sdssurveys Twitter account will be run by SDSS observer, Audrey Oravetz. Audrey is part of the staff of observers and fiber optic technicians (the people who plug optical fibers into the plates) working for SDSS at our survey telescope in Apache Point, New Mexico (our telescope is neither automated, nor robotic, despite the common misconception!).

Audrey Oravetz

SDSS Observer, Audrey Oravetz (she’s definitely not a robot).

Here’s Audrey introducing herself in her own words:

Hello. My name is Audrey Oravetz and I have worked as an observer for the 2.5m SDSS telescope for the past nine years. It was always a dream of mine to work at a high-ranking observatory. I enjoy working alongside my colleagues to output a high quantity of quality data for the SDSS projects.

I graduated from the University of Colorado at Boulder in 2007 with a B.A. in Astrophysics and graduated from NMSU with a M.S. degree last summer. My thesis (under the supervision of Dr. Rene Walterbos (NMSU)) was centered around the study of ionizing H-alpha photons within two star formation nebulae, NGC346 and NGC602, within the SMC.

A Winter Night at APO

It’s almost March, and spring is in the air in much of the Northern Hemisphere, but here’s a beautiful Haiku written by SDSS Observer Patrick Gaulme as part of his SDSS 2.5m Observing Log for the night of Monday January 4th 2016 [Observed 1.5 h – Lost 9.9 for weather].

– A Winter night at APO –

No water in the faucets
Few photons in the bucket
Silent snow in the dead of night


A winter night at APO, Image Credit: Patrick Gaulme, SDSS.

We all agree this lovely poem really captures the essence of observing in a snowy night, and we also think it demonstrates the huge range of talent found amongst the dedicated crew of SDSS observers working at Apache Point Observatory.

Letter from the New Editor in Chief

Dear Readers of the SDSS Blog,

I am Zheng Zheng, a SDSS-IV postdoctoral research fellow at the National Astronomical Observatories, Chinese Academy of Sciences (NAOC). I will be your new Editor in Chief for the SDSS Blog for the next 6 months and I will try my best to work with other bloggers to make the blog posts more interesting and smooth.

I got my PhD at Johns Hopkins University and now I am a postdoctoral researcher working at the NAOC and partially at the Institute of Cosmology and Gravity (ICG) at the University of Portsmouth in the U.K. I am currently studying extra-galactic galaxies using the SDSS-IV MaNGA data. I am also interested/involved in MaNGA stellar library, APOGEE and eBOSS projects.

As you may have known, the SDSS is an internationally collaborated survey project and the member institutes come from all over the world. In the future, we will introduce more interesting SDSS related sciences/events from all over the world, including the U.S., Europe, East Asia, and South America. We are aiming to a post frequency of about 1 ‘long’ post (like the ones introducing science projects) per 1-2 weeks. We will also have ‘short’ posts reporting SDSS related events and/or short news.

Please do not hesitate to make comments and let us know your ideas about the blog posts. Your feedback is highly appreciated and we will try our best to post more articles according to your interests.


Zheng Zheng


Zheng observing at Palomar

Tweep of the Week: Anne-Marie Weijmans

The MaNGA Lead Observer, and our Data Release Co-ordinator, Anne-Marie Weijmans will be spending some time at Apache Point Observatory Dec 8-17th and has agreed to take over the @sdssurveys Twitter account for the trip. We’re hoping for some tweets about pie (as well as observing).

MaNGA Lead Observer (Anne-Marie Weijmans) plugging IFUs into an SDSS plate. Credit: SDSS.

MaNGA Lead Observer (Anne-Marie Weijmans) plugging IFUs into an SDSS plate. Credit: SDSS.


Dr. Weijmans is a Lecturer (Assistant Prof. for our US readers) and Leverhulme Early Career Fellow based at the University of St Andrews in Scotland. Her research interests concentrate on the structure and evolution of early-type (i.e. visually smooth) galaxies using Integral Field Spectroscopy. Before joining MaNGA she was a member of the ATLAS-3D survey, which was one of the first surveys to use this technique on a sample of galaxies.

Spotlight on APOGEE: Gail Zasowski and Cosmic Dust

Meet Gail Zasowski — postdoctoral research fellow at Johns Hopkins University and one of the people behind creating the APOGEE-2 target sample. She earned her PhD at the University of Virginia in 2012 and was then awarded an NSF fellowship at The Ohio State University. She is now a postdoctoral research fellow at Johns Hopkins University. One of Gail’s research interests is the interstellar medium (ISM), and this blog post will introduce how she has used APOGEE to study dust and molecules in the ISM.


Gail grew up in western New York and in Knoxville, Tennessee. In college, she double majored in physics and Latin. As a PhD candidate at UVa, she studied dusty young protostars, the distribution of dust in the Milky Way Galaxy, and stellar populations in open clusters, that is, determining their ages and distances.

One of her explorations with APOGEE data has been in a unique approach to studying diffuse interstellar bands (DIBs), which are absorption features seen in many optical and near-infrared spectra that are believed to be due to large molecules in the ISM. These features are found in nearly every APOGEE spectrum, because the ISM lies between the Earth and every star that we study. The exact nature of these large molecules has been a question for some decades. In one paper, Gail and her collaborators demonstrated that DIBs trace the known distribution of dust throughout the ISM (check out the cool graphic below, from a press release), and can be used to independently verify the large-scale structure of the Milky Way Galaxy.

Gail successfully mapped the strength of DIB features in APOGEE spectra across the Milky Way Galaxy, and used them to show that DIBs trace the distribution of cosmic dust in between stars, but can also be used to trace large scale structure as well.

Gail successfully mapped the strength of DIB features in APOGEE spectra across the Milky Way Galaxy, and used them to show that DIBs trace the distribution of cosmic dust in between stars, but can also be used to trace large scale structure as well. The high latitude data comes from Ting-Wen Lan at JHU.

Even cooler, Gail also found evidence for circumstellar (that is, surrounding a particular star) DIBs in the dusty protoplanetary nebula MWC 922. This is an exciting result: it shows that the molecules that create DIBs are not merely confined to the ISM, but can be found in dusty environments around stars, too. And this is important because one of the unanswered questions about large molecules in space is how they are formed. Placing them around stars, and perhaps eventually showing that they originate around stars before being put in the ISM, would be a major step forward in cosmic dust studies.

Now Gail wants to apply her knowledge of surveys like APOGEE to create models of galaxies that can be used to understand resolved stellar populations (like the Milky Way’s) and unresolved stellar populations (such as the faint light that can be seen in more distant galaxies). This ties in well with several SDSS surveys, which study individual stars (e.g., APOGEE and SEGUE) and entire distant galaxies (e.g., MaNGA. Such a comparison should shed light on those parts of the Milky Way that are not well understood (such as its location in the Tully-Fisher plane, which can be used to determine a galaxy’s mass), as well as tell us about specific properties concerning other galaxies that show similarity to the Milky Way.

Do you think that all work and no play has made Gail a dull astronomer? Not at all! She was a founding member of the Dark Skies, Bright Kids! program at the University of Virginia, which seeks to provide science education in an informal setting to rural, underserved school children in central Virginia. She runs an annual space camp in Columbus, Ohio, that is aimed at middle school students. She is part of the Committee for the Participation of Women in SDSS, which seeks to promote gender balance and an inclusive environment within the collaboration, whose findings were published recently and can be read about on this blog. She also supports LGBTQ initiatives within her own department at JHU.

Gail’s wide-ranging interests, and those of her colleagues, have made a positive impact on the APOGEE survey — not only is it useful for stellar populations studies (which is what it is designed for), but it can also be used to study cosmic dust!

Spotlight on APOGEE: Jonathan Bird and the Formation of the Milky Way

The spotlight this month is on Jonathan Bird, the Vanderbilt Initiative for Data-Intensive Astrophysics Postdoc (VIDA) at Vanderbilt University. He is also the APOGEE-2 Science co-chair, for which he is responsible of “making sure that APOGEE-2 takes full advantage of the truly ground-breaking dataset the survey has produced.”

Jonathan is fascinated by the structure of the Milky Way Galaxy: Why is it shaped this way? What was it like in the past? And what will it be like in the future?


Like many people, Jonathan developed a love for astronomy from an early age. His family home in the Santa Monica mountains offered beautiful views of the night sky.

But growing up, his real passion was basketball. He travelled extensively across the west and southwest for tournaments in high school, and was lucky enough to play college ‘ball when he arrived at Caltech — a team in need of little introduction.

Jonathan’s scientific interests have been widespread. Studying radio waves to investigate what determines the large-scale morphology of galaxies; using Cepheid variable stars to measure distances to galaxies; studying Asymptotic Giant Branch stars in order to understand their contribution to stellar synthesis models, a major component of galaxy models; and studying how a disk galaxy is assembled from smaller galaxies. Do you see a theme? In fact, Jonathan’s major interests can best be described by his PhD thesis title: “The Formation and Evolution of Disk Galaxies.” Jonathan’s goal is nothing less than understanding how the Milky Way came to be, how it evolved, and where it is going from here.

Perhaps that is why Jonathan fits in so well with the APOGEE team.

Let’s show one of Jonathan’s models from his 2013 paper on disk galaxy assembly. In the top left panel is shown the distribution of really old stars (11-12 billion years old) in a typical spiral galaxy. From left to right, and then continuing on the bottom, each panel shows the distribution of stars in a different age group (numbers in the bottom right of each panel show the age in billions of years). Notice that the “spiral” shape that we associate with spiral galaxies is found only among stars that are less than about 2 billion years old. As odd as this may seem, this is exactly what astronomers observe: the older stars are found across a large volume across the bulge and halo; whereas younger stars are predominantly found in the disk, where star formation is ongoing.


How does this model hold up against the huge APOGEE-1 dataset? Pretty well, actually. For Jonathan, this is heartening — we have begun to piece together the massively complex stellar history of the Milky Way Galaxy, and we can do it with state-of-the-art telescopes and computer codes. You can follow more about what Jonathan is doing, along with the rest of the APOGEE-2 team, by following us on social media.