Cosmic Surveys

Cosmological surveys map out the distribution of matter in the universe. Some surveys may target a particular type of object by looking for a very particular spectral signal. For example, the HETDEX survey is designed to find a class of galaxies, Lyman-$\alpha$ emitters, at a time when the universe was about 10-11 billion years younger than it is today. By precisely measuring how those galaxies are receding from us, HETDEX will provide a new constraint on the expansion rate of the universe and the role of dark energy in the past. Other surveys collect light across a wider range of frequencies. For example, the Rubin Observatory Legacy Survey of Space and Time (LSST) will take optical images of a large fraction of the sky, nearly every night. LSST will detect nearly 4 billion galaxies that can be measured so precisely that distortions in galaxy shapes due to gravity can be used, statistically, to map out how both dark and luminous matter are distributed in the Universe. Because LSST will image the same part of the sky so often, it will also capture the variations of light emitted by objects that are changing rapidly, allowing studies of the dynamic universe.



IGC members who study Cosmic Surveys


NameRoleAffiliationEmailPhoneOffice AddressAffiliated Center(s) Research Topics(s)
Tommy Chin Graduate Student Physics wjc5509@psu.edu 6692331822 301D Whitmore Laboratory IGC, CFT, CTOC Cosmic Surveys, Black Holes, Quantum Universe, Dynamic Universe
Robin Ciardullo Faculty Astronomy rbc3@psu.edu +1 814 865 6601 525 Davey Laboratory CMA, CTOC Cosmic Surveys
Caryl Gronwall Faculty Astronomy cag18@psu.edu +1 814 865 2918 417B Davey Laboratory CTOC, CMA Cosmic Surveys, Astrostatistics
Joel Leja Faculty Astronomy, ICDS jql6565@psu.edu +1 814 865 0418 515 Davey Laboratory CTOC Cosmic Surveys
Greg Lukens Graduate Student Astronomy gmlukens@psu.edu +1 814 865 0419 441 Davey Laboratory CTOC Cosmic Surveys
Donald Schneider Faculty Astronomy dps7@psu.edu +1 814 863 9554 508 Davey Laboratory CTOC Black Holes, Cosmic Surveys
Sarah Shandera Faculty Physics ses47@psu.edu +1 814 863 9595 303A Whitmore Laboratory CFT Quantum Universe, Cosmic Surveys, Black Holes, Gravitational Waves, Dark Matter
Zhenyuan Wang Graduate Student zzw173@psu.edu +1 814 865 0419 532 C Davey Laboratory CTOC Cosmic Surveys
Bingjie Wang Postdoc ICDS, Astronomy bwang@psu.edu +1 814 865 0418 520 Davey Laboratory IGC Cosmic Surveys

News about Cosmic Surveys


IGC Grad Students Kallan Berglund and Mary Ogborn win 2023 Pennsylvania Space Grant Consortium Graduate Research Fellowships from NASA

2023-07-11

Pennsylvania Space Grant Consortium Graduate Research Fellowships annually provides a one-year fellowship of $5,000 to outstanding Penn State students pursuing graduate study leading to masters or doctoral degrees in STEM fields that promote the understanding, assessment and utilization of space and contribute to NASA’s Mission Directorates. In keeping with the National Space Grant College and Fellowship Program goals, scholars agree to participate in mentoring or educational outreach activities for a minimum of 10 hours per semester.

2023 fellowship recipients from the Eberly College of Science students are:

Kallan Berglund, physics Clancy McIntyre, biology Mary Ogborn, astronomy and astrophysics Michael Palumbo, astronomy and astrophysics

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Bright light from early universe 'opens new chapter in astronomy'

2022-11-30

UNIVERSITY PARK, Pa. — An unexpectedly rich array of early galaxies that was largely hidden until now has been observed by researchers using data from NASA’s James Webb Space Telescope.

The researchers found two exceptionally bright galaxies that existed approximately 350 and 450 million years after the big bang. Their extreme brightness is puzzling to astronomers and challenges existing models of galaxy formation.

“These objects are remarkable because they are far brighter than we would expect from our models of how galaxies form,” said Joel Leja, assistant professor of astronomy and astrophysics at Penn State, who developed the code used to analyze light from the distant galaxies.

As a postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics, Leja developed code capable of making sense of infrared data from distant galaxies, such as those imaged by Webb, proving that they are in fact our first glimpses of the very early universe.

“The code combines models of all the things that live in galaxies and interprets the light we observe from them,” said Leja. “This includes things like stars of various ages and elemental compositions, cosmic dust that blocks the light we see from stars, emission from gaseous nebulae, and so on.”

Two research papers, one led by Marco Castellano of the National Institute for Astrophysics in Rome, Italy, and another by Rohan Naidu of the Harvard-Smithsonian Center for Astrophysics and the Massachusetts Institute of Technology with Leja as co-author, have been published in the Astrophysical Journal Letters. The two papers describe the bright celestial objects, which both teams discovered separately in quick succession just days after Webb officially started science operations.

“With Webb, we were amazed to find the most distant starlight that anyone had ever seen, just days after Webb released its first data,” Naidu said in a NASA news release.

With just four days of analysis, the researchers found two exceptionally bright galaxies. They determined the young galaxies transformed gas into stars extremely rapidly, meaning the onset of stellar birth may have started just 100 million years after the big bang, roughly 13.8 billion years ago. The researchers also determined the two galaxies existed approximately 450 and 350 million years after the big bang, though future spectroscopic measurements with Webb will help confirm their findings.

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Bright Light from Early Universe 'Opens New Chapter in Astronomy'

2022-11-21

UNIVERSITY PARK, Pa. — An unexpectedly rich array of early galaxies that was largely hidden until now has been observed by researchers using data from NASA’s James Webb Space Telescope.

The researchers found two exceptionally bright galaxies that existed approximately 350 and 450 million years after the big bang. Their extreme brightness is puzzling to astronomers and challenges existing models of galaxy formation.

“These objects are remarkable because they are far brighter than we would expect from our models of how galaxies form,” said Joel Leja, assistant professor of astronomy and astrophysics at Penn State, who developed the code used to analyze light from the distant galaxies.

As a postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics, Leja developed code capable of making sense of infrared data from distant galaxies, such as those imaged by Webb, proving that they are in fact our first glimpses of the very early universe.

“The code combines models of all the things that live in galaxies and interprets the light we observe from them,” said Leja. “This includes things like stars of various ages and elemental compositions, cosmic dust that blocks the light we see from stars, emission from gaseous nebulae, and so on.”

Two research papers, one led by Marco Castellano of the National Institute for Astrophysics in Rome, Italy, and another by Rohan Naidu of the Harvard-Smithsonian Center for Astrophysics and the Massachusetts Institute of Technology with Leja as co-author, have been published in the Astrophysical Journal Letters. The two papers describe the bright celestial objects, which both teams discovered separately in quick succession just days after Webb officially started science operations.

“With Webb, we were amazed to find the most distant starlight that anyone had ever seen, just days after Webb released its first data,” Naidu said in a NASA news release.

With just four days of analysis, the researchers found two exceptionally bright galaxies. They determined the young galaxies transformed gas into stars extremely rapidly, meaning the onset of stellar birth may have started just 100 million years after the big bang, roughly 13.8 billion years ago. The researchers also determined the two galaxies existed approximately 450 and 350 million years after the big bang, though future spectroscopic measurements with Webb will help confirm their findings.

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The Hobby-Eberly Telescope reaches 25th anniversary milestone

2022-11-03

One of the world’s largest optical telescopes, the Hobby-Eberly telescope (HET) at the University of Texas at Austin’s McDonald Observatory, is marking 25 years of investigating the mysteries of the cosmos. The HET’s unique and innovative design was developed by Penn State professors Lawrence W. Ramsey, who has served as the HET’s project scientist and as the chairman of its board of directors, and Daniel W. Weedman in the early 1980s.

The telescope is named for Robert E. Eberly, a Penn State alumnus and benefactor, for whom Penn State’s Eberly College of Science is also named, and former Texas Lieutenant-Governor William P. Hobby.

“This year marks an important milestone for the Hobby-Eberly telescope,” said Taft Armandroff, the Frank and Susan Bash Endowed Chair at UT Austin, Director of McDonald Observatory, and HET board chair. “The HET provides the resources that our faculty and researchers from many different institutions use to do cutting-edge science.”

First dedicated in 1997, the HET is currently a collaboration of four institutions: the University of Texas at Austin, Penn State, the University of Munich, and the University of Goettingen. The telescope, which has an 11-meter (433-inch) primary mirror, received a major upgrade in 2016, expanding its field-of-view to capture a section of the night sky 120-times larger than before. This capability and new instruments were celebrated in a re-dedication event in 2017.

“In addition to its enormous light-gathering power, the HET’s scheduling system allows it to rapidly respond to unusual, transient events in the heavens,” said Ramsey, emeritus professor of astronomy and astrophysics and Eberly College of Science Distinguished Senior Scholar. “This combination allows HET to address a wide range of scientific questions, ranging from exoplanets to the large-scale structure of the universe. In the HET’s first quarter-century, over 450 peer-reviewed papers relied on HET data.”

The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) is an international collaboration that is probing dark energy, the mysterious force that is accelerating the expansion of the universe, to build an extensive three-dimensional map of the universe when it was but a fraction of its current age. By training the HET on two regions of the sky, one near the Big Dipper and one near Orion, the telescope is capturing the cosmic fingerprint of the light from 2.5 million galaxies. Astronomers are using the Visible Integral-field Replicable Unit Spectrograph, which can simultaneously obtain over 30,000 spectra in a 20-minute exposure, to address a number of fundamental questions, in particular why the expansion of the universe is speeding up over time.

“The HETDEX program involves not only the four university partners but dozens of additional scientists at several institutions from around the world,” said Donald Schneider, distinguished professor in the Department of Astronomy and Astrophysics at Penn State and a HET board member.

HET has played an integral role in finding Earth-sized planets beyond our solar system. The Habitable Zone Planet Finder (HPF), developed by a team of scientists led by Penn State Professor of Astronomy and Astrophysics Suvrath Mahdevan, aims to identify so-called “Goldilocks planets,” exoplanets capable of supporting liquid water on their surfaces. One discovery involved K2-25b, a planet the size of Neptune orbiting a cool star. Using high-time resolution HPF spectroscopy of the system when the planet passed between Earth and the star, astronomers were able to determine the angle between the star’s equator and the orbit of the planet, which offers insights into the formation and evolution of planetary systems.

“A lot of the public thinks science has these eureka moments, but most major scientific discoveries are met with ‘hmm, that’s funny,’” said Bill Cochran, research professor at UT Austin and chair of the HET Users Committee. “Whether or not a planet is habitable is not the right question. I am interested in how the planet evolved, and I want to use the findings with the HPF to pursue these questions with my colleagues in different disciplines.”

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NASA selects STAR-X for $3M mission concept study

2022-08-30

STAR-X, the Survey and Time-domain Astrophysical Research Explorer, a proposed NASA Medium-Class Explorer (MIDEX) mission that includes Penn State astronomer Niel Brandt, has been selected by the NASA Explorers Program for further study. STAR-X is one of two proposed MIDEX missions that will receive $3 million for a nine-month detailed study of mission requirements. At the end of this period, one of the proposed missions will be selected for a target launch date in 2027-2028 and be eligible for up to $300 million in additional funding.

Comprised of an X-ray telescope, an ultraviolet (UV) telescope, and a responsive spacecraft, STAR-X is designed to conduct time-domain surveys, which study how astronomical objects change with time, and to respond rapidly to transient cosmic events discovered by other observatories such as LIGO, Rubin LSST, the Roman Space Telescope, and the Square Kilometer Array. The mission is led by Principal Investigator William Zhang at NASA’s Goddard Space Flight Center (GSFC) in Greenbelt, Maryland. Penn State’s Brandt, who is the Verne M. Willaman Professor of Astronomy and Astrophysics and Professor of Physics, is involved in planning the STAR-X cosmic X-ray surveys, active galaxy studies, and fast X-ray transient studies.

“I can’t wait to use STAR-X to investigate the first supermassive black holes and understand mysterious, explosive X-ray transient sources,” said Brandt. “STAR-X will also provide the essential X-ray and UV follow-up capabilities for remarkable cosmic objects discovered by the Rubin LSST in optical light.”

The STAR-X spacecraft would be able to turn rapidly to point a sensitive wide-field X-ray telescope and a UV telescope at transient cosmic sources, such as supernova explosions and feeding supermassive black holes. Deep X-ray surveys would map black holes and hot gas trapped in distant clusters of galaxies; combined with infrared observations from NASA’s upcoming Roman Space Telescope, these observations would trace how massive clusters of galaxies built up over cosmic history.

STAR-X would provide revolutionary capabilities including unprecedented X-ray and UV volumetric survey speed; a unique combination of large field-of-view, large X-ray collecting area, low background, and excellent imaging; increased sensitivity for characterizing diffuse emissions, and increased speed and sensitivity for the discovery of faint X-ray point sources. It fills the gap in X-ray and UV survey coverage, providing simultaneous X-ray and UV observations, which are among the earliest and most uniquely informative astrophysical signals that probe the inner regions around compact objects like black holes and neutron stars, and it complements optical, infrared, and gravitational wave facilities.

The mission’s Deputy Principal Investigator, Ann Hornschemeier, who is also Lab Chief for X-ray Astrophysics at GSFC, earned a Ph.D. in Astronomy and Astrophysics at Penn State, mentored by Brandt, in 2002.

“Ann is superb - a bundle of energy, and the right person to push STAR-X to succeed,” said Brandt.

NASA Explorer missions conduct focused scientific investigations and develop instruments that fill scientific gaps between the agency’s larger space science missions. The proposals were competitively selected based on potential science value and feasibility of development plans. The Explorers Program is the oldest continuous NASA program and is designed to provide frequent, low-cost access to space using principal investigator-led space science investigations relevant to the Science Mission Directorate’s astrophysics and heliophysics programs.

“NASA’s Explorers Program has a proud tradition of supporting innovative approaches to exceptional science, and these selections hold that same promise,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate at NASA Headquarters in Washington. “From studying the evolution of galaxies to explosive, high-energy events, these proposals are inspiring in their scope and creativity to explore the unknown in our universe.”

Since the launch of Explorer 1 in 1958, which discovered the Earth’s radiation belts, the Explorers Program has launched more than 90 missions, including the Uhuru and Cosmic Background Explorer (COBE) missions that led to Nobel prizes for their investigators.

The program is managed by NASA Goddard for NASA’s Science Mission Directorate in Washington, which conducts a wide variety of research and scientific exploration programs for Earth studies, space weather, the solar system, and the universe. More information can be found at the Explorers Program website (https://explorers.gsfc.nasa.gov/).

Further technical details about the observatory are available at (http://star-x.xraydeep.org/observatory/).

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