Diving for pearls with the Hubble Space Telescope
Astronomy and Space Science

RIT astronomers help find star ‘necklace’ connecting elliptical galaxies


(NASA, ESA and RIT) The NASA/ESA Hubble Space Telescope captured a cosmic moment of two merging cluster galaxies connected by a bright blue string of young stars.

Jul. 10, 2014
Susan Gawlowicz

Stars forming like a string of blue pearls along two elliptical galaxies could be the result of a galactic merger, according to an international team of astronomers. The structure could reveal rare insights about elliptical galaxies.

Scientists from Rochester Institute of Technology helped analyze data from the Hubble Space Telescope showing elliptical galaxies coalescing at the core of a dense galaxy cluster. The study is part of a program sponsored by the Hubble Space Telescope—an international cooperation between NASA and the European Space Agency—to look inside 23 massive clusters first catalogued in the Sloan Digital Sky Survey.

Findings of the study, “A thirty-kiloparsec chain of ‘beads-on-a-string’ star formation between two merging early type galaxies in the core of a strong-lensing galaxy cluster,” are available online, at http://arxiv.org/abs/1407.2251 and in an upcoming issue of The Astrophysical Journal Letters.

“These data were originally taken for a completely different purpose—to study the bluish arcs on larger scales in the cluster,” said Chris O’Dea, professor in RIT’s School of Physics and Astronomy and a co-author on the paper. “We were not expecting to catch these two elliptical galaxies in this spectacular burst of star formation.”

O’Dea and co-author Stefi Baum, professor and director of RIT’s Chester F. Carlson Center for Imaging Science, were thesis advisers and mentors of the paper’s lead author, Grant Tremblay, a post-doctoral fellow at the European Southern Observatory in Garching, Germany, and an inaugural alumnus of RIT’s astrophysical sciences and technology Ph.D. program. Tremblay will join Yale University as a NASA Einstein Fellow in September.



(NASA, ESA and RIT) A zoom-in shows the two merging central cluster galaxies in yellow/orange and the “beads-on-a-string” star formation in bright blue.

The 100,000-light-year-long structure identified in the Hubble data is dotted with 19 young, blue star clusters like pearls on a string, evenly spaced and separated by 3,000 light-years. The star necklace will lose its shape in about 10 million years as each of the 19 stellar superclusters follows a different orbit, Tremblay said.

Earlier observations of star clusters forming in evenly distributed clumps in spiral galaxies could explain Tremblay’s “serendipitous discovery” in the Hubble data.

“This phenomenon has never been seen before in merging elliptical galaxies,” Tremblay said. “We have two big monsters and they’re playing tug-of-war with this necklace.”

Tremblay and his team suggest three possible scenarios that could have created the string-of-pearl stars between two elliptical galaxies:

  • Merger—Coalescing galaxies triggered a reservoir of cold gas into star formation
  • Cooling flow of gas—Hot gas from the X-ray atmosphere around the galaxies cooled into puddles of cold molecular gas and started to form stars
  • Collision—A galactic collision created an X-ray shock catalyzing the star formation by compressing the gas and cooling the plasma.

“Compared to a galaxy’s lifetime of billions of years, star formation processes—which take millions of years—are quite brief,” said Kevin Cooke, graduate student in RIT’s astrophysical sciences and technology program. “To find such an event in early type galaxies where star formation is rare is an incredibly fortunate find. Research into star formation in galaxies helps address many fundamental questions about the universe, and this rare star formation event will help propel this field of knowledge.”

Tremblay’s team has a strong connection to his alma mater, RIT, with three co-authors from the university—Baum, O’Dea and Cooke. In addition to the RIT contingent, the team of scientists includes Michael Gladders, University of Chicago; Matthew Bayliss, Harvard University and Harvard-Smithsonian Center for Astrophysics; Håkon Dahle, University of Oslo; Timothy Davis, European Southern Observatory; Michael Florian, University of Chicago; Jane Rigby, NASA Goddard Space Flight Center; Keren Sharon, University of Michigan; Emmaris Soto, the Catholic University of America; and Eva Wuyts, Max-Planck-Institut für extraterrestrische Physik.

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Original Source: RIT University News

Taking Landsat 8 to the Beach (Summary)
Remote Sensing

Some things go perfectly with a summer trip to the coast: sunscreen, mystery novels, cold beverages, and sand castles. Other things—like algae blooms or polluted runoff—are a lot less appealing. The newest generation of Landsat satellite is helping researchers identify and study potential problem areas from space.

Aug. 22, 2014
Kate Ramsayer, with Michael Carlowicz
Taking Landsat 8 to the Beach
acquired September 19, 2013download large image (5 MB, JPEG, 3021x2014)
acquired September 19, 2013download GeoTIFF file (11 MB, TIFF)
Taking Landsat 8 to the Beach
acquired September 19, 2013
Color bar for Taking Landsat 8 to the Beach

Most remote sensing satellites, including the long-running Landsats, detect the intensity of different wavelengths of light that reflect off of Earth’s surfaces, from forests to fields to cities. But water poses a challenge. It absorbs and scatters a lot of light, so oceans and lakes tend to look dark or lack detail on satellite images, especially in the murky waters near the coast. “All of the interesting stuff was typically lost in the noise of the old instruments,” said John Schott, a researcher at the Rochester Institute of Technology.

Landsat 8, however, has a new “coastal blue band” designed to parse out subtle differences in the color of water—minor changes in color intensity that can indicate what is mixed in that water. “Now we’ve got a possibility to see and figure out what’s causing color changes,” said Schott, a Landsat science team member. “It’s a potential revolution for studying water.”

The natural-color image at the top of this page was acquired on September 19, 2013, by the Operational Land Imager (OLI) on Landsat 8. It shows a southern shore of Lake Ontario near Rochester, New York, as it might appear to the human eye.

Beyond the blue of that water, Schott and his colleagues are paying close attention to three colors—green, yellow, and gray—to decipher what’s floating in Lake Ontario. Green wavelengths indicate the presence of chlorophyll, the molecule found not only in land plants but also algae and other phytoplankton. Yellow usually hints at the presence of decaying plant matter. Grays come from airborne particulates like dust and soil, or from dead algae that have lost their chlorophyll.

“It’s a classic color problem. All of these things together give the water a color,” Schott said. “You can unmix these to give you the components.” That’s exactly what his research team is now doing.

Over the past year, members of Schott’s research group have paddled or motored out into the lake to sample the waters on the same days that Landsat 8 has passed overhead (which happens once every 16 days). The team then compares the chemistry and visual quality of those water samples with what the satellite sees. The researchers are using these comparisons to create data tables and computer programs that will eventually turn remote satellite images into timely information for local managers of water quality.

The area inside the inset box of the top image is shown in scientific detail in the two lower images. The left map uses wavelength data from OLI to show the levels of chlorophyll in the lake and nearshore water bodies. Plants and phytoplankton use this pigment to convert photons of light into food. The lower right map uses Landsat data to show the amount of suspended sediment in the water. Silt, soil, sand, dissolved plant matter (from microscopic algae to leaves), and other floating debris naturally flow out from inland waterways to the coast, carrying both nutrients and pollutants.

NASA Earth Observatory images by Jesse Allen, using data provided courtesy of John Schott and Javier Concha, Rochester Institute of Technology. Caption by Kate Ramsayer, with Michael Carlowicz.

Landsat 8 - OLI
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Source: NASA Earth Observatory

Preethi Vaidyanathan

PhD Candidate
Other Degrees: Electrical Eng., KNMIET, India; MS, Electrical Eng., RIT
Hometown: Lucknow, India

While pursuing my Masters in Electrical Engineering at RIT I became interested in image processing, which tuned me into Imaging Science. In my first year as a PhD student I worked as a research assistant to Dr. Naval Rao on an interesting medical imaging project, after which I started my PhD work with Dr. Jeff Pelz on Eye tracking & Computational Linguistics to Understand Images. Working in the Multidisciplinary Vision Research Lab has helped me meet so many students and faculty from different departments across RIT, and broadened my perspective about how to do research. CIS has supported me to publish papers and attend conferences around the world such as the Europoean Conference on Eye Movements and the 2014 Symposium on Eye Tracking Research & Applications. Although networking is difficult for someone who is used to sitting in front of a computer, the welcoming environment at CIS encourages me to talk to faculty, staff, and students despite any background differences. I am glad I took advantage of pursuing this PhD when CIS & RIT gave me the opportunity to do so. As an Imaging Scientist I will never run out of research questions and innovative answers!

Dave Kelbe, PhD 2015

Other Degrees: BS, Imaging Science, RIT
Hometown: Victor, NY

I have always loved photography, but more than the art, I was drawn to an understanding of how the camera worked and how I could manipulate it to produce better images based on the science and physics of the underlying imaging processes. I was looking for something more fresh, more invigorating than physics or engineering... Imaging science was the perfect fit. It is specific enough that it is acutely relevant, yet encompassing enough that it is widely needed in almost any discipline.  While studying abroad freshman year, I discovered a connection to CIS all the way over in New Zealand and realized that the world was a lot smaller than I thought. I’ve since collected field measurements in the savanna of South Africa, squeezed into an unpressurized aircraft fuselage with the next-generation AVIRIS hyperspectral sensor in California,  climbed flux towers dizzyingly high above the forest canopy in Michigan, and worked alongside Greek Orthodox monks at a monastery in the Sinai desert to help recover erased texts from ancient manuscripts using spectral imaging. I’m incredibly thankful for the academic community in CIS that doesn’t stifle the energetic pursuits of the student, but supports and encourages them.

Wei Yao, PhD

UNDERGRADUATE PROGRAM AND SCHOOL: Electrical Engineering, Chongqing University, Chongqing, China

HOMETOWN: Wuwei, Gansu Province, China

When I worked as an electrical engineer in a medical imaging equipment manufacturing company, I wanted to learn the knowledge of biomedical imaging and digital image processing. Then I found Imaging Science. At CIS, I have learned a wide variety of courses, and met professors in many interesting majors. I changed my research topic from biomedical imaging to remote sensing imaging in my second year; now I am working on a NASA-supported project which studies the world’s ecosystems using two imaging spectrometers on a satellite. From photons to a photo, Imaging Science fuels the discovery of everything related to images.

Danny Dang, BS

I wanted to be a part of Imaging Science at RIT because of its distinctive curriculum. Imaging Science, to me, is a unique mixture of computer programing, math, physics, and head bashing. The Center for Imaging Science is special because of how it fosters close relationships not only between students within the major, but also with faculty and staff.  Thanks to these connections, I have been able to perform research on wavefront sensing with Prof. Jie Qiao in the AOFIM (Advanced Optical Fabrication and Instrumentation in Metrology) Lab.  Imaging Science is a major full of opportunities; you need only to take advantage of them. 

Imaging science is a unique holistic program that applies aspects of physics, engineering, computer science, and psychology to understanding and using images for all types of scientific inquiry.
Michael Augspurger
Imaging Science BS '17
There is so much covered by the term 'imaging science' that I’ve been exposed to far more topics and research areas than I would have in a traditional program.
Oesa Weaver
Imaging Science PhD '15
My internship at the National Ecological Observatory Network was a real-world job experience where co-workers came to me for information on Image Processing, and I realized that I was the expert in the office.
Kevin Sacca
Imaging Science BS '16

RIT imaging science Ph.D. student promotes photonics funding on congressional visit
Remote Sensing
Student Stories

Amanda Ziemann attended national conferences, won best student poster award

May. 19, 2014
Susan Gawlowicz


Rochester Institute of Technology graduate student Amanda Ziemann participated in the National Photonics Initiative Congressional Visits Day in Washington, D.C., on May 9 to promote government funding and investment in photonics-driven technology critical to the nation’s competitiveness and security.

Ziemann, a Ph.D. student at RIT’s Chester F. Carlson Center for Imaging Science and native of Getzville, N.Y., and a resident of South Burlington, Vt., represented the professional organization SPIE (the International Society for Optics and Photonics) in support of the National Photonics Initiative, an alliance of industry, academia and government. The initiative lobbies to develop photonics—or scientific applications using light—in advanced manufacturing, communications and information technology, defense and national security, energy and health and medicine.

The congressional visit coincided with the SPIE annual conference in Baltimore on May 5–9, where Ziemann presented her paper, “Hyperspectral target detection using graph theory models and manifold geometry via an adaptive implementation of locally linear embedding.” She spent the day following her presentation meeting with congressional staffers representing Vermont, Maryland and New Mexico with SPIE members from the National Oceanic and Atmospheric Administration and a defense contractor from Albuquerque, N.M.

“In participating in the congressional visits, I provided the perspective of current STEM graduate students that will be entering the photonics workforce,” said Ziemann, who expects to graduate in May 2015. “My graduate research is funded through the Department of Defense, and one of our concerns moving forward is the decrease in government allocated funding for academic research. There is a well-documented graying of the scientific and technical workforce in the aerospace community, and without stable academic funding the U.S. will continue to fall behind in these areas.”

SPIE leadership invited Ziemann on the congressional visit at the suggestion of David Messinger, the director of the Digital Imaging and Remote Sensing Laboratory at RIT’s Center for Imaging Science.

“Amanda’s research is helping to develop and implement the next generation of approaches to how we analyze these complex data sets,” Messinger said. “Interestingly, because of the nature of the data and her approaches, we may ultimately be able to use these methods in other areas besides imaging. Her work in this area only further underscores the need for the development of the next generation of scientists and engineers in these fields related to optics and imaging.”

Earlier this spring, Ziemann also attended a U.S. Department of Energy Conference on Data Analysis in Sante Fe, N.M., March 5–7, where she won first prize in the Statistics in Defense and National Security student poster award and $400 for her research, “Using Graph Theory Models and Manifold Learning to Analyze Cluttered Hyperspectral Scenes.”

“My research focuses on applying advanced mathematical concepts, taken from the fields of data mining and computational graph theory, to analyze complex imagery,” Ziemann said. “This imagery can be collected from airborne platforms or satellites and is called ‘hyperspectral imaging’—images collected not in three colors, such as red, green and blue, but in hundreds of colors. The sensors that collect these images capture information beyond what the human eye can see, allowing researchers to better differentiate materials within the scene for applications including mapping natural disasters, tracking the spread of diseased crops and monitoring urban development.”

The Statistical Sciences Group at Los Alamos National Laboratory hosted the conference highlighting collaborative research conducted by scientists, statisticians and data analysts across the Department of Energy. Topics included data-intensive applied science, uncertainty quantification, national security, big data and exascale computing, energy and the environment, and signature discovery.

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Original Source: RIT University News