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Astronomers Use Hubble and Keck to Identify Dwarf Galaxy
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By NASA
ESA/Hubble & NASA, M. J. Koss, A. J. Barth The light that the NASA/ESA Hubble Space Telescope collected to create this image reached the telescope after a journey of 250 million years. Its source was the spiral galaxy UGC 11397, which resides in the constellation Lyra (The Lyre). At first glance, UGC 11397 appears to be an average spiral galaxy: it sports two graceful spiral arms that are illuminated by stars and defined by dark, clumpy clouds of dust.
What sets UGC 11397 apart from a typical spiral lies at its center, where a supermassive black hole containing 174 million times the mass of our Sun grows. As a black hole ensnares gas, dust, and even entire stars from its vicinity, this doomed matter heats up and puts on a fantastic cosmic light show.
Material trapped by the black hole emits light from gamma rays to radio waves, and can brighten and fade without warning. But in some galaxies, including UGC 11397, thick clouds of dust hide much of this energetic activity from view in optical light. Despite this, UGC 11397’s actively growing black hole was revealed through its bright X-ray emission — high-energy light that can pierce the surrounding dust. This led astronomers to classify it as a Type 2 Seyfert galaxy, a category used for active galaxies whose central regions are hidden from view in visible light by a donut-shaped cloud of dust and gas.
Using Hubble, researchers will study hundreds of galaxies that, like UGC 11397, harbor a supermassive black hole that is gaining mass. The Hubble observations will help researchers weigh nearby supermassive black holes, understand how black holes grew early in the universe’s history, and even study how stars form in the extreme environment found at the very center of a galaxy.
Text credit: ESA
Image credit: ESA/Hubble & NASA, M. J. Koss, A. J. Barth
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By NASA
2 min read
Hubble Captures an Active Galactic Center
This Hubble image shows the spiral galaxy UGC 11397. ESA/Hubble & NASA, M. J. Koss, A. J. Barth The light that the NASA/ESA Hubble Space Telescope collected to create this image reached the telescope after a journey of 250 million years. Its source was the spiral galaxy UGC 11397, which resides in the constellation Lyra (The Lyre). At first glance, UGC 11397 appears to be an average spiral galaxy: it sports two graceful spiral arms that are illuminated by stars and defined by dark, clumpy clouds of dust.
What sets UGC 11397 apart from a typical spiral lies at its center, where a supermassive black hole containing 174 million times the mass of our Sun grows. As a black hole ensnares gas, dust, and even entire stars from its vicinity, this doomed matter heats up and puts on a fantastic cosmic light show.
Material trapped by the black hole emits light from gamma rays to radio waves, and can brighten and fade without warning. But in some galaxies, including UGC 11397, thick clouds of dust hide much of this energetic activity from view in optical light. Despite this, UGC 11397’s actively growing black hole was revealed through its bright X-ray emission — high-energy light that can pierce the surrounding dust. This led astronomers to classify it as a Type 2 Seyfert galaxy, a category used for active galaxies whose central regions are hidden from view in visible light by a donut-shaped cloud of dust and gas.
Using Hubble, researchers will study hundreds of galaxies that, like UGC 11397, harbor a supermassive black hole that is gaining mass. The Hubble observations will help researchers weigh nearby supermassive black holes, understand how black holes grew early in the universe’s history, and even study how stars form in the extreme environment found at the very center of a galaxy.
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
Claire Andreoli (claire.andreoli@nasa.gov)
NASA’s Goddard Space Flight Center, Greenbelt, MD
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Last Updated Jun 27, 2025 Related Terms
Hubble Space Telescope Keep Exploring Discover More Topics From Hubble
Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
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By NASA
4 Min Read NASA Tech to Use Moonlight to Enhance Measurements from Space
NASA's Arcstone instrument will be the first mission exclusively dedicated to measuring moonlight, or lunar reflectance, from space as a way to calibrate and improve science data collected by Earth-viewing, in-orbit instruments. Credits: Blue Canyon Technologies NASA will soon launch a one-of-a-kind instrument, called Arcstone, to improve the quality of data from Earth-viewing sensors in orbit. In this technology demonstration, the mission will measure sunlight reflected from the Moon— a technique called lunar calibration. Such measurements of lunar spectral reflectance can ultimately be used to set a high-accuracy, universal standard for use across the international scientific community and commercial space industry.
To ensure satellite and airborne sensors are working properly, researchers calibrate them by comparing the sensor measurements against a known standard measurement. Arcstone will be the first mission exclusively dedicated to measuring lunar reflectance from space as a way to calibrate and improve science data collected by Earth-viewing, in-orbit instruments.
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This visualization demonstrates how Arcstone will operate while in orbit measuring lunar reflectance to establish a new calibration standard for future Earth-observing remote sensors. Arcstone’s satellite platform was manufactured by Blue Canyon Technologies. NASA/Tim Marvel/Blue Canyon Technologies “One of the most challenging tasks in remote sensing from space is achieving required instrument calibration accuracy on-orbit,” said Constantine Lukashin, principal investigator for the Arcstone mission and physical scientist at NASA’s Langley Research Center in Hampton, Virginia. “The Moon is an excellent and available calibration source beyond Earth’s atmosphere. The light reflected off the Moon is extremely stable and measurable at a very high level of detail. Arcstone’s goal is to improve the accuracy of lunar calibration to increase the quality of spaceborne remote sensing data products for generations to come.”
Across its planned six-month mission, Arcstone will use a spectrometer — a scientific instrument that measures and analyzes light by separating it into its constituent wavelengths, or spectrum — to measure lunar spectral reflectance. Expected to launch in late June as a rideshare on a small CubeSat, Arcstone will begin collecting data, a milestone called first light, approximately three weeks after reaching orbit.
“The mission demonstrates a new, more cost-efficient instrument design, hardware performance, operations, and data processing to achieve high-accuracy reference measurements of lunar spectral reflectance,” said Lukashin.
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Measuring the lunar reflectance at the necessary ranges of lunar phase angles and librations is required to build a highly accurate lunar reference. A satellite platform in space would provide this required sampling. Arcstone will use a spectrometer to demonstrate the ability to observe and establish a data record of lunar spectral reflectance throughout its librations and phases for other instruments to use the Moon to calibrate sensors.NASA/Scientific Visualization Studio Measurements of lunar reflectance taken from Earth’s surface can be affected by interference from the atmosphere, which can complicate calibration efforts. Researchers already use the Sun and Moon to calibrate spaceborne instruments, but not at a level of precision and agreement that could come from having a universal standard.
Lukashin and colleagues want to increase calibration accuracy by getting above the atmosphere to measure reflected solar wavelengths in a way that provides a stable and universal calibration source. Another recent NASA mission, called the Airborne Lunar Spectral Irradiance mission also used sensors mounted on high-altitude aircraft to improve lunar irradiance measurements from planes.
There is not an internationally accepted standard (SI-traceable) calibration for lunar reflectance from space across the scientific community or the commercial space industry.
“Dedicated radiometric characterization measurements of the Moon have never been acquired from a space-based platform,” said Thomas Stone, co-investigator for Arcstone and scientist at the U.S. Geological Survey (USGS). “A high-accuracy, SI-traceable lunar calibration system enables several important capabilities for space-based Earth observing missions such as calibrating datasets against a common reference – the Moon, calibrating sensors on-orbit, and the ability to bridge gaps in past datasets.”
The Arcstone spacecraft with solar panels installed as it is tested before being integrated for launch. Blue Canyon Technologies If the initial Arcstone technology demonstration is successful, a longer Arcstone mission could allow scientists to make the Moon the preferred reference standard for many other satellites. The new calibration standard could also be applied retroactively to previous Earth data records to improve their accuracy or fill in data gaps for data fields. It could also improve high-precision sensor performance on-orbit, which is critical for calibrating instruments that may be sensitive to degradation or hardware breakdown over time in space.
“Earth observations from space play a critical role in monitoring the environmental health of our planet,” said Stone. “Lunar calibration is a robust and cost-effective way to achieve high accuracy and inter-consistency of Earth observation datasets, enabling more accurate assessments of Earth’s current state and more reliable predictions of future trends.”
The Arcstone technology demonstration project is funded by NASA’s Earth Science Technology Office’s In-space Validation of Earth Science Technologies. Arcstone is led by NASA’s Langley Research Center in partnership with Colorado University Boulder’s Laboratory for Atmospheric and Space Physics, USGS, NASA Goddard Space Flight Center in Greenbelt, Maryland, Resonon Inc., Blue Canyon Technologies, and Quartus Engineering.
For more information on NASA’s Arcstone mission visit:
https://science.larc.nasa.gov/arcstone/about/
About the Author
Charles G. Hatfield
Science Public Affairs Officer, NASA Langley Research Center
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Last Updated Jun 20, 2025 LocationNASA Langley Research Center Related Terms
Science-enabling Technology Earth Earth Science Earth Science Division Earth's Moon General Goddard Space Flight Center Langley Research Center Lunar Science Science Instruments Science Mission Directorate Small Satellite Missions Technology Explore More
3 min read NASA Measures Moonlight to Improve Earth Observations
Article 2 months ago Keep Exploring Discover More Topics From NASA
Missions
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By NASA
Explore Hubble Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts Multimedia Images Videos Sonifications Podcasts e-Books Online Activities 3D Hubble Models Lithographs Fact Sheets Posters Hubble on the NASA App Glossary News Hubble News Social Media Media Resources More 35th Anniversary Online Activities 2 min read
Hubble Studies Small but Mighty Galaxy
This NASA/ESA Hubble Space Telescope features the nearby galaxy NGC 4449. ESA/Hubble & NASA, E. Sabbi, D. Calzetti, A. Aloisi This portrait from the NASA/ESA Hubble Space Telescope puts the nearby galaxy NGC 4449 in the spotlight. The galaxy is situated just 12.5 million light-years away in the constellation Canes Venatici (the Hunting Dogs). It is a member of the M94 galaxy group, which is near the Local Group of galaxies that the Milky Way is part of.
NGC 4449 is a dwarf galaxy, which means that it is far smaller and contains fewer stars than the Milky Way. But don’t let its small size fool you — NGC 4449 packs a punch when it comes to making stars! This galaxy is currently forming new stars at a much faster rate than expected for its size, which makes it a starburst galaxy. Most starburst galaxies churn out stars mainly in their centers, but NGC 4449 is alight with brilliant young stars throughout. Researchers believe that this global burst of star formation came about because of NGC 4449’s interactions with its galactic neighbors. Because NGC 4449 is so close, it provides an excellent opportunity for Hubble to study how interactions between galaxies can influence the formation of new stars.
Hubble released an image of NGC 4449 in 2007. This new version incorporates several additional wavelengths of light that Hubble collected for multiple observing programs. These programs encompass an incredible range of science, from a deep dive into NGC 4449’s star-formation history to the mapping of the brightest, hottest, and most massive stars in more than two dozen nearby galaxies.
The NASA/ESA/CSA James Webb Space Telescope has also observed NGC 4449, revealing in intricate detail the galaxy’s tendrils of dusty gas, glowing from the intense starlight radiated by the flourishing young stars.
Text Credit: ESA/Hubble
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
Claire Andreoli (claire.andreoli@nasa.gov)
NASA’s Goddard Space Flight Center, Greenbelt, MD
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Last Updated Jun 20, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
Hubble Space Telescope Astrophysics Astrophysics Division Galaxies Goddard Space Flight Center Irregular Galaxies The Universe Keep Exploring Discover More Topics From Hubble
Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Hubble’s Galaxies
Galaxy Details and Mergers
Hubble’s Night Sky Challenge
View the full article
-
By European Space Agency
Astronomers have discovered a huge filament of hot gas bridging four galaxy clusters. At 10 times as massive as our galaxy, the thread could contain some of the Universe’s ‘missing’ matter, addressing a decades-long mystery.
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