skip to content

Institute of Astronomy

 

Fri 07 Mar 13:00: Symmetries and topology of extremal horizons

Next External Talks - Mon, 03/03/2025 - 11:33
Symmetries and topology of extremal horizons

We establish an intrinsic rigidity theorem for extremal horizons, showing that a compact cross-section of a rotating extremal horizon must admit a Killing vector field. This result holds for a wide class of matter theories, extending work by Dunajski and Lucietti in the vacuum case. In four-dimensional Einstein-Maxwell theory, it follows that any non-trivial cross-section must be given by the extremal Kerr-Newman family. We also discuss the implications for the near-horizon geometry and the topology of cross-sections. This talk is partly based on joint work with David Katona and James Lucietti.

Add to your calendar or Include in your list

Categories: Talks

Mon 03 Mar 13:40: Strong lensing and stellar kinematics of cluster galaxies

Next Wednesday Seminars - Mon, 03/03/2025 - 11:25
Strong lensing and stellar kinematics of cluster galaxies

As the most massive gravitationally bound structures in the Universe, galaxy clusters frequently act as strong gravitational lenses. Strong lensing (SL) enables us to reconstruct the total mass distribution of a cluster with extreme accuracy, providing insights into the physical properties of dark matter and its interplay with baryons. SL models are also crucial for studying magnified high-redshift sources and measuring cosmological parameters from observed time delays between lensed variable sources. However, the accuracy of SL models is limited by parametric degeneracy, which hinders the reconstruction of the mass distribution of cluster members. This degeneracy can be resolved using independent information from their stellar kinematics. After a general introduction to SL by galaxy clusters, I will present how we leveraged deep MUSE /VLT observations of SL clusters to build a large catalogue of accurate stellar velocity dispersion measurements of early-type member galaxies. These measurements serve as the foundation for calibrating new scaling relations that describe their structure in a set of highly accurate SL models and for comparisons with cosmological hydrodynamical simulations of galaxy clusters, aimed at testing the ΛCDM paradigm.

Add to your calendar or Include in your list

Categories: Talks

Mon 03 Mar 13:15: Metal enrichment of a dusty star-forming galaxies at the EoR with JWST/INIRSpec IFS

Next Wednesday Seminars - Mon, 03/03/2025 - 11:23
Metal enrichment of a dusty star-forming galaxies at the EoR with JWST/INIRSpec IFS

With the recent discovery of quiescent galaxies at z>3, studying of dusty star-forming galaxies at high redshift became more vital than ever, as they are thought to be precursors of quiescent galaxies. However, until the launch of JWST , studying the rest-frame of optical emission of these sources at redshifts higher than 3 was out of reach of astronomers, often solely relying on the ALMA observations of their FIR emission lines. In this talk, I will present one of the first JWST /NIRSpec IFS data of a massive dusty star-forming galaxy at the Epoch of Reionisation. COS -3018, is a unique UV bright galaxy (LUV>2 L*) at z~6.8, previously only observed using ALMA ([CII]158 microns, [OIII] 88 microns), VLT X -Shooter (Lyman-alpha) and HST broadband photometry. Furthermore, this galaxy has a large amount of dust (log Mdust =10.7 Msol) and an excess of [OIII]88micron emission suggesting that this might be an AGN or has non-standard ISM conditions such as AGN . I will present deep high-resolution JWST /NIRSpec IFS observations of rest-frame UV and optical continuum and emission lines, in combination with deep ALMA [CII] and [OIII]88micron observations and NIR Cam photometry. Using the deep and unique NIR Spec IFS (PRISM+R2700) observations, I will show the ISM conditions in this unique galaxy: excitation conditions (extreme star formation or AGN ?), metallicity gradient, location of dust obscured (from ALMA high resolution observations) and unobscured star formation. Finally, I will answer the question: What is driving such an extreme production of dust in this galaxy and UV luminosity in this galaxy?

Add to your calendar or Include in your list

Categories: Talks

The asteroid hits and near-misses you never hear about

Astronomy News - Mon, 03/03/2025 - 10:11

Since a potentially hazardous asteroid was detected in December, tens of others objects have come close to Earth.

Mon 03 Mar 14:00: Exoplanets and the Road to the Radius Valley

Next External Talks - Sun, 02/03/2025 - 22:28
Exoplanets and the Road to the Radius Valley

The observed population of small, close-in exoplanets is bifurcated into two distinct types by the so-called ‘radius valley’. In this talk, I will discuss the atmospheric escape processes that may affect such planets and finally lead to the radius gap being carved out, specifically X-ray/EUV photoevaporation, core-powered mass loss, and boil-off. The latter process is an extreme mass loss mechanism that is triggered by protoplanetary disc dispersal and may have lasting impacts on the population of small exoplanets.

Add to your calendar or Include in your list

Categories: Talks

Touchdown! Carrying NASA Science, Firefly’s Blue Ghost Lands on Moon

Astronomy News - Sun, 02/03/2025 - 15:31
First image captured by Firefly’s Blue Ghost lunar lander, taken shortly after confirmation of a successful landing at Mare Crisium on the Moon’s near side. This is the second lunar delivery of NASA science and tech instruments as part of the agency’s Commercial Lunar Payload Services initiative.Credit: Firefly Aerospace

Carrying a suite of NASA science and technology, Firefly Aerospace’s Blue Ghost Mission 1 successfully landed at 3:34 a.m. EST on Sunday near a volcanic feature called Mons Latreille within Mare Crisium, a more than 300-mile-wide basin located in the northeast quadrant of the Moon’s near side.

The Blue Ghost lander is in an upright and stable configuration, and the successful Moon delivery is part of NASA’s CLPS (Commercial Lunar Payload Services) initiative and Artemis campaign. This is the first CLPS delivery for Firefly, and their first Moon landing.  

The 10 NASA science and technology instruments aboard the lander will operate on the lunar surface for approximately one lunar day, or about 14 Earth days.

“This incredible achievement demonstrates how NASA and American companies are leading the way in space exploration for the benefit of all,” said NASA acting Administrator Janet Petro. “We have already learned many lessons – and the technological and science demonstrations onboard Firefly’s Blue Ghost Mission 1 will improve our ability to not only discover more science, but to ensure the safety of our spacecraft instruments for future human exploration – both in the short term and long term.”

Since launching from NASA’s Kennedy Space Center in Florida on Jan. 15, Blue Ghost traveled more than 2.8 million miles, downlinked more than 27 GB of data, and supported several science operations. This included signal tracking from the Global Navigation Satellite System (GNSS) at a record-breaking distance of 246,000 miles with the Lunar GNSS Receiver Experiment payload – showing NASA can use the same positioning systems on Earth when at the Moon. Science conducted during the journey also included radiation tolerant computing through the Van Allen Belts with the Radiation-Tolerant Computer System payload and measurements of magnetic field changes in space with the Lunar Magnetotelluric Sounder payload.

“The science and technology we send to the Moon now helps prepare the way for future NASA exploration and long-term human presence to inspire the world for generations to come,” said Nicky Fox, associate administrator for science at NASA Headquarters in Washington. “We’re sending these payloads by working with American companies – which supports a growing lunar economy.”

During surface operations, the NASA instruments will test and demonstrate lunar subsurface drilling technology, regolith sample collection capabilities, global navigation satellite system abilities, radiation tolerant computing, and lunar dust mitigation methods. The data captured will benefit humanity by providing insights into how space weather and other cosmic forces impact Earth.  

Before payload operations conclude, teams will aim to capture imagery of the lunar sunset and how lunar dust reacts to solar influences during lunar dusk conditions, a phenomenon first documented by former NASA astronaut Eugene Cernan on Apollo 17. Following the lunar sunset, the lander will operate for several hours into the lunar night.

“On behalf of our entire team, I want to thank NASA for entrusting Firefly as their lunar delivery provider,” said Jason Kim, CEO of Firefly Aerospace. “Blue Ghost’s successful Moon landing has laid the groundwork for the future of commercial exploration across cislunar space. We’re now looking forward to more than 14 days of surface operations to unlock even more science data that will have a substantial impact on future missions to the Moon and Mars.”

To date, five vendors have been awarded 11 lunar deliveries under CLPS and are sending more than 50 instruments to various locations on the Moon, including the lunar South Pole. Existing CLPS contracts are indefinite-delivery, indefinite-quantity contracts with a cumulative maximum contract value of $2.6 billion through 2028. 

Learn more about NASA’s CLPS initiative at:

https://www.nasa.gov/clps

-end-

Amber Jacobson / Karen Fox 
Headquarters, Washington
202-358-1600
amber.c.jacobson@nasa.gov / karen.c.fox@nasa.gov 

Natalia Riusech / Nilufar Ramji
Johnson Space Center, Houston
281-483-5111
nataila.s.riusech@nasa.gov / nilufar.ramji@nasa.gov

Antonia Jaramillo
Kennedy Space Center, Florida
321-501-8425
antonia.jaramillobotero@nasa.gov

Share Details Last Updated Mar 02, 2025 LocationNASA Headquarters Related Terms

NASA set to launch SPHEREx space telescope to scan entire sky

Astronomy News - Sat, 01/03/2025 - 10:25

NASA's newest space telescope will scan the entire sky in a range of near-infrared wavelengths to help astronomers better understand the evolution of the universe and search for promising spots for extraterrestrial life

Fri 23 May 11:30: Title to be confirmed

IoA Institute of Astronomy Talk Lists - Fri, 28/02/2025 - 11:05
Title to be confirmed

Abstract not available

Add to your calendar or Include in your list

Infrared space telescope will probe ‘inflation’ after Big Bang

Astronomy News - Fri, 28/02/2025 - 11:04
Science, Volume 387, Issue 6737, Page 913-914, February 2025.

How to see every planet in the solar system at once this week

Astronomy News - Fri, 28/02/2025 - 11:04

For a few evenings around 28 February, every planet in the solar system will be visible in the night sky, thanks to a rare great planetary alignment. Here's how to make sure you don't miss this planetary parade.

NASA’s Hubble Provides Bird’s-Eye View of Andromeda Galaxy’s Ecosystem

Astronomy News - Fri, 28/02/2025 - 11:03
Explore Hubble 5 Min Read NASA’s Hubble Provides Bird’s-Eye View of Andromeda Galaxy’s Ecosystem A view of the distribution of known satellite galaxies orbiting the large Andromeda galaxy (M31), located 2.5 million light-years away.  Credits:
NASA, ESA, Alessandro Savino (UC Berkeley), Joseph DePasquale (STScI), Akira Fujii DSS2

Located 2.5 million light-years away, the majestic Andromeda galaxy appears to the naked eye as a faint, spindle-shaped object roughly the angular size of the full Moon. What backyard observers don’t see is a swarm of nearly three dozen small satellite galaxies circling the Andromeda galaxy, like bees around a hive.

These satellite galaxies represent a rambunctious galactic “ecosystem” that NASA’s Hubble Space Telescope is studying in unprecedented detail. This ambitious Hubble Treasury Program used observations from more than a whopping 1,000 Hubble orbits. Hubble’s optical stability, clarity, and efficiency made this ambitious survey possible. This work included building a precise 3D mapping of all the dwarf galaxies buzzing around Andromeda and reconstructing how efficiently they formed new stars over the nearly 14 billion years of the universe’s lifetime.

This is a wide-angle view of the distribution of known satellite galaxies orbiting the large Andromeda galaxy (M31), located 2.5 million light-years away. The Hubble Space Telescope was used to study the entire population of 36 mini-galaxies circled in yellow. Andromeda is the bright spindle-shaped object at image center. All the dwarf galaxies seem to be confined to a plane, all orbiting in the same direction. The wide view is from ground-based photography. Hubble’s optical stability, clarity, and efficiency made this ambitious survey possible. Hubble close up snapshots of four dwarf galaxies are on image right. The most prominent dwarf galaxy is M32 (NGC 221), a compact ellipsoidal galaxy that might be the remnant core of a larger galaxy that collided with Andromeda a few billion years ago. NASA, ESA, Alessandro Savino (UC Berkeley), Joseph DePasquale (STScI), Akira Fujii DSS2

In the study published in The Astrophysical Journal, Hubble reveals a markedly different ecosystem from the smaller number of satellite galaxies that circle our Milky Way. This offers forensic clues as to how our Milky Way galaxy and Andromeda have evolved differently over billions of years. Our Milky Way has been relatively placid. But it looks like Andromeda has had a more dynamic history, which was probably affected by a major merger with another big galaxy a few billion years ago. This encounter, and the fact that Andromeda is as much as twice as massive as our Milky Way, could explain its plentiful and diverse dwarf galaxy population.

Surveying the Milky Way’s entire satellite system in such a comprehensive way is very challenging because we are embedded inside our galaxy. Nor can it be accomplished for other large galaxies because they are too far away to study the small satellite galaxies in much detail. The nearest galaxy of comparable mass to the Milky Way beyond Andromeda is M81, at nearly 12 million light-years.

This bird’s-eye view of Andromeda’s satellite system allows us to decipher what drives the evolution of these small galaxies. “We see that the duration for which the satellites can continue forming new stars really depends on how massive they are and on how close they are to the Andromeda galaxy,” said lead author Alessandro Savino of the University of California at Berkeley. “It is a clear indication of how small-galaxy growth is disturbed by the influence of a massive galaxy like Andromeda.”

“Everything scattered in the Andromeda system is very asymmetric and perturbed. It does appear that something significant happened not too long ago,” said principal investigator Daniel Weisz of the University of California at Berkeley. “There’s always a tendency to use what we understand in our own galaxy to extrapolate more generally to the other galaxies in the universe. There’s always been concerns about whether what we are learning in the Milky Way applies more broadly to other galaxies. Or is there more diversity among external galaxies? Do they have similar properties? Our work has shown that low-mass galaxies in other ecosystems have followed different evolutionary paths than what we know from the Milky Way satellite galaxies.”

For example, half of the Andromeda satellite galaxies all seem to be confined to a plane, all orbiting in the same direction. “That’s weird. It was actually a total surprise to find the satellites in that configuration and we still don’t fully understand why they appear that way,” said Weisz.

To view this video please enable JavaScript, and consider upgrading to a web browser that
supports HTML5 video

This animation begins with a view of the neighboring Andromeda galaxy. We zoom through a scattering of foreground stars and enter the inky blackness of intergalactic space. We cross 2.5 million light-years to reach the Andromeda system, consisting of 36 dwarf satellite galaxies orbiting the giant spindle-shaped Andromeda galaxy at image center. An ambitious survey by the Hubble Space Telescope was made to plot the galaxy locations in three-dimensional space. In this video we circle around a model of the Andromeda system based on real Hubble observational data. NASA, ESA, Christian Nieves (STScI), Alessandro Savino (UC Berkeley); Acknowledgment: Joseph DePasquale (STScI), Frank Summers (STScI), Robert Gendler

The brightest companion galaxy to Andromeda is Messier 32 (M32). This is a compact ellipsoidal galaxy that might just be the remnant core of a larger galaxy that collided with Andromeda a few billion years ago. After being gravitationally stripped of gas and some stars, it continued along its orbit. Galaxy M32 contains older stars, but there is evidence it had a flurry of star formation a few billion years ago. In addition to M32, there seems to be a unique population of dwarf galaxies in Andromeda not seen in the Milky Way. They formed most of their stars very early on, but then they didn’t stop. They kept forming stars out of a reservoir of gas at a very low rate for a much longer time.

“Star formation really continued to much later times, which is not at all what you would expect for these dwarf galaxies,” continued Savino. “This doesn’t appear in computer simulations. No one knows what to make of that so far.”

“We do find that there is a lot of diversity that needs to be explained in the Andromeda satellite system,” added Weisz. “The way things come together matters a lot in understanding this galaxy’s history.”

Hubble is providing the first set of imaging where astronomers measure the motions of the dwarf galaxies. In another five years Hubble or NASA’s James Webb Space Telescope will be able to get the second set of observations, allowing astronomers to do a dynamical reconstruction for all 36 of the dwarf galaxies, which will help astronomers to rewind the motions of the entire Andromeda ecosystem billions of years into the past.

The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.

Explore More
NASA’s Hubble Traces Hidden History of Andromeda Galaxy


Hubble’s High-Definition Panoramic View of the Andromeda Galaxy


Explore the Night Sky: Messier 31


Hubble’s Galaxies

Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble

Media Contact:

Claire Andreoli (claire.andreoli@nasa.gov)
NASA’s Goddard Space Flight CenterGreenbelt, Maryland

Ray Villard
Space Telescope Science Institute, Baltimore, Maryland

Science Contact:

Alessandro Savino
University of California, Berkeley, California

Share Details Last Updated Feb 27, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms 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.


Galaxy Details and Mergers


Reshaping Our Cosmic View: Hubble Science Highlights


Hubble’s Night Sky Challenge

Our Galaxy’s central black hole puts on a fireworks show

Astronomy News - Fri, 28/02/2025 - 11:02

Nature, Published online: 27 February 2025; doi:10.1038/d41586-025-00578-2

The James Webb Space Telescope uncovered repeated flares from the supermassive object called Sagittarius A*.

Variability of Central Stars of Planetary Nebulae with the Zwicky Transient Facility. II. Long-Timescale Variables including Wide Binary and Late Thermal Pulse Candidates

Planetary systems - Thu, 27/02/2025 - 10:20
arXiv:2502.18651v1 Announce Type: new Abstract: In this second paper on the variability survey of central stars of planetary nebulae (CSPNe) using ZTF, we focus on the 11 long-timescale variables with variability timescales ranging from months to years. We also present preliminary analyses based on spectroscopic and/or photometric follow-up observations for six of them. Among them is NGC 6833, which shows a 980 day periodic variability with strange characteristics: 'triangle-shaped' brightening in $r$, $i$, and WISE bands but almost coincidental shallow dips in the $g$-band. We speculate this to be a wide but eccentric binary with the same orbital period. Long-period near-sinusoidal variability was detected in two other systems, NGC 6905 and Kn 26, with periods of 700 days and 230 days, respectively, making them additional wide-binary candidates. The latter also shows a short period at 1.18 hours which can either be from a close inner binary or pulsational origin. We present CTSS 2 and PN K 3-5 which show brightening and significant reddening over the whole ZTF baseline. A stellar model fit to the optical spectrum of CTSS 2 reveals it to be one of the youngest post-AGB CSPN known. Both show high-density emission-line cores. These appear to be late thermal pulse candidates, currently evolving towards the AGB phase, though alternative explanations are possible. We then present recent HST/COS ultraviolet spectroscopy of the known wide-binary candidate LoTr 1 showing that the hot star is a spectroscopic twin of the extremely hot white dwarf in UCAC2 46706450. We think that the long photometric period of 11 years is the binary orbital period. Finally, we briefly discuss the ZTF light curves of the remaining variables, namely Tan 2, K 3-20, WHTZ 3, Kn J1857+3931, and IPHAS J1927+0814. With these examples, we present the effectiveness of the von Neumann statistics and Pearson Skew-based metric space in searching for long-timescale variables.

Variability of Central Stars of Planetary Nebulae with the Zwicky Transient Facility. II. Long-Timescale Variables including Wide Binary and Late Thermal Pulse Candidates

Recent IoA Publications - Thu, 27/02/2025 - 10:20
arXiv:2502.18651v1 Announce Type: new Abstract: In this second paper on the variability survey of central stars of planetary nebulae (CSPNe) using ZTF, we focus on the 11 long-timescale variables with variability timescales ranging from months to years. We also present preliminary analyses based on spectroscopic and/or photometric follow-up observations for six of them. Among them is NGC 6833, which shows a 980 day periodic variability with strange characteristics: 'triangle-shaped' brightening in $r$, $i$, and WISE bands but almost coincidental shallow dips in the $g$-band. We speculate this to be a wide but eccentric binary with the same orbital period. Long-period near-sinusoidal variability was detected in two other systems, NGC 6905 and Kn 26, with periods of 700 days and 230 days, respectively, making them additional wide-binary candidates. The latter also shows a short period at 1.18 hours which can either be from a close inner binary or pulsational origin. We present CTSS 2 and PN K 3-5 which show brightening and significant reddening over the whole ZTF baseline. A stellar model fit to the optical spectrum of CTSS 2 reveals it to be one of the youngest post-AGB CSPN known. Both show high-density emission-line cores. These appear to be late thermal pulse candidates, currently evolving towards the AGB phase, though alternative explanations are possible. We then present recent HST/COS ultraviolet spectroscopy of the known wide-binary candidate LoTr 1 showing that the hot star is a spectroscopic twin of the extremely hot white dwarf in UCAC2 46706450. We think that the long photometric period of 11 years is the binary orbital period. Finally, we briefly discuss the ZTF light curves of the remaining variables, namely Tan 2, K 3-20, WHTZ 3, Kn J1857+3931, and IPHAS J1927+0814. With these examples, we present the effectiveness of the von Neumann statistics and Pearson Skew-based metric space in searching for long-timescale variables.

Glacial isostatic adjustment reveals Mars’s interior viscosity structure

Astronomy News - Thu, 27/02/2025 - 10:14

Nature, Published online: 26 February 2025; doi:10.1038/s41586-024-08565-9

Emplacement of the north polar cap of Mars is investigated by combining viscoelastic deformation calculations and observations, showing that it formed over the last 1.7–12.0 Myr atop a stiff lithosphere and high-viscosity mantle (1022 Pa s), and that glacial isostatic adjustment could be further constrained.

Meet the ice-hunting robots headed for the Moon right now

Astronomy News - Thu, 27/02/2025 - 10:13

Nature, Published online: 27 February 2025; doi:10.1038/d41586-025-00597-z

Two US probes launched today, one laden with a drill and a hopper looking for lunar water.

Seeing the Outer Edge of the Infant Type Ia Supernova 2024epr in the Optical and Near Infrared

Stars and stellar evolution - Wed, 26/02/2025 - 10:55
arXiv:2502.17556v1 Announce Type: new Abstract: We present optical-to-near infrared (NIR) photometry and spectroscopy of the Type Ia supernova (SN Ia) 2024epr, including NIR spectra observed within two days of first light. The early-time optical spectra show strong, high-velocity Ca and Si features near rarely-observed velocities at $\sim$0.1$c$, and the NIR spectra show a \CI\ "knee." Despite these high-velocity features at early times, SN~2024epr evolves into a normal SN Ia, albeit with stronger peak-light Ca absorption than other SNe Ia with the same light curve shape. Although we infer a normal decline rate, $\Delta m_{15}(B)=1.09\pm0.12$ mag, from the light-curve rise, SN 2024epr is a Branch "cool" object and has red early-time colors ($g-r\approx0.15$ mag at $-10$ days). The high velocities point to a density enhancement in the outer layers of the explosion, but thick-shell He-detonation models do not match the smoothly rising light curve or lack of He in our early-time NIR spectra. No current models (e.g., delayed detonation or thin He shell double detonation) appear to reproduce all of the observed properties. Such constraints are only possible for SN 2024epr from the earliest optical and NIR observations, highlighting their importance for constraining SN Ia models. Finally, we find several other SNe Ia with intermediate mass elements at $\sim$30\,000 km s$^{-1}$ within days after the explosion that evolve into otherwise normal SNe Ia at peak light, suggesting the early-time spectra of SNe Ia may hide a broad diversity of observational characteristics.