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Institute of Astronomy

 

Large gas inflow driven by a matured galactic bar in the early Universe

Astronomy News - Thu, 22/05/2025 - 08:34

Nature, Published online: 21 May 2025; doi:10.1038/s41586-025-08914-2

Gas distribution and motion patterns driven by a galactic bar of the J0107a dusty star-forming galaxy have analogues in local bars, indicating that similar processes of active star formation were already operating 11.1 billion years ago.

Unexpected clustering pattern in dwarf galaxies challenges formation models

Astronomy News - Thu, 22/05/2025 - 08:34

Nature, Published online: 21 May 2025; doi:10.1038/s41586-025-08965-5

Unexpected large-scale clustering of isolated, diffuse and blue dwarf galaxies, comparable to that seen for massive galaxy groups, challenges current models of cosmology and galaxy evolution.

Dying stars give a second wind to exoplanet formation

Astronomy News - Thu, 22/05/2025 - 08:33

Nature, Published online: 21 May 2025; doi:10.1038/d41586-025-01445-w

The binary star system ν Octantis has long been considered hostile to planet formation. The discovery of a white dwarf in the system offers an alternative view.

Discovery Alert: A Possible Perpendicular Planet

Astronomy News - Thu, 22/05/2025 - 08:33
Explore This Section Artist’s concept of a planet orbiting two brown dwarfs. The planet is in a polar orbit (red), perpendicular to the mutual orbit of the two brown dwarfs (blue). ESO/L. Calçada The Discovery

A newly discovered planetary system, informally known as 2M1510, is among the strangest ever found. An apparent planet traces out an orbit that carries it far over the poles of two brown dwarfs. This pair of mysterious objects – too massive to be planets, not massive enough to be stars – also orbit each other. Yet a third brown dwarf orbits the other two at an extreme distance.

Key Facts

In a typical arrangement, as in our solar system, families of planets orbit their parent stars in more-or-less a flat plane – the orbital plane – that matches the star’s equator. The rotation of the star, too, aligns with this plane. Everyone is “coplanar:” flat, placid, stately.

Not so for possible planet 2M1510 b (considered a “candidate planet” pending further measurements). If confirmed, the planet would be in a “polar orbit” around the two central brown dwarfs – in other words, its orbital plane would be perpendicular to the plane in which the two brown dwarfs orbit each other. Take two flat disks, merge them together at an angle in the shape of an X, and you have the essence of this orbital configuration.

“Circumbinary” planets, those orbiting two stars at once, are rare enough. A circumbinary orbiting at a 90-degree tilt was, until now, unheard of. But new measurements of this system, using the ESO (European Southern Observatory) Very Large Telescope in Chile, appear to reveal what scientists previously only imagined. 

Details

The method by which the study’s science team teased out the planet’s vertiginous existence is itself a bit of a wild ride. The candidate planet cannot be detected the way most exoplanets – planets around other stars – are found today: the “transit” method, a kind of mini-eclipse, a tiny dip in starlight when the planet crosses the face of its star.

Instead they used the next most prolific method, “radial velocity” measurements. Orbiting planets cause their stars to rock back and forth ever so slightly, as the planets’ gravity pulls the stars one way and another; that pull causes subtle, but measurable, shifts in the star’s light spectrum. Add one more twist to the detection in this case: the push-me-pull-you effect of the planet on the two brown dwarfs’ orbit around each other. The path of the brown dwarf pair’s 21-day mutual orbit is being subtly altered in a way that can only be explained, the study’s authors conclude, by a polar-orbiting planet.

Fun Facts

Only 16 circumbinary planets – out of more than 5,800 confirmed exoplanets – have been found by scientists so far, most by the transit method. Twelve of those were found using NASA’s now-retired Kepler Space Telescope, the mission that takes the prize for the most transit detections (nearly 2,800). Scientists have observed a small number of debris disks and “protoplanetary” disks in polar orbits, and suspected that polar-orbiting planets might be out there as well. They seem at last to have turned one up.

The Discoverers

An international science team led by Thomas A. Baycroft, a Ph.D. student in astronomy and astrophysics at the University of Birmingham, U.K., published a paper describing their discovery in the journal “Science Advances” in April 2025. The planet was entered into NASA’s Exoplanet Archive on May 1, 2025. The system’s full name is 2MASS J15104786-281874 (2M1510 for short).

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China is readying a mission to two rocky bodies in our solar system

Astronomy News - Thu, 22/05/2025 - 08:30

China's ambitious Tianwen-2 mission will soon be heading to two extremely different space rocks, and should provide vital data to help us understand the nature of asteroids and comets

Weird planet is orbiting backwards between two stars

Astronomy News - Thu, 22/05/2025 - 08:30

After two decades of debate, research confirms that an odd binary star system has an equally odd planetary companion

Thu 29 May 14:00: Planet Migration in Dusty Protoplanetary Disks

Next External Talks - Wed, 21/05/2025 - 12:17
Planet Migration in Dusty Protoplanetary Disks

Fast inward migration of planetary cores embedded in gaseous disks is a common problem in the current planet formation paradigm. Even though dust is ubiquitous in protoplanetary disks, its dynamical role in the migration history of planetary embryos has not been considered until recently. In this talk, I will show that a planetesimal embedded in a dusty disk leads to an asymmetric dust-density distribution that can exert a net torque under conditions relevant to planetary embryos up to several Earth masses. Building on the results or a large suite of numerical simulations for measuring this dust torque under a wide range of conditions, I will present the first study showing that dust torques can have a significant impact on the migration and formation history of planetary embryos.

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A JWST View of the Overmassive Black Hole in NGC 4486B

Recent IoA Publications - Wed, 21/05/2025 - 10:36
arXiv:2505.14676v1 Announce Type: new Abstract: We present a new stellar dynamical measurement of the supermassive black hole (SMBH) in the compact elliptical galaxy NGC 4486B, based on integral field spectroscopy with JWST/NIRSpec. The two-dimensional kinematic maps reveal a resolved double nucleus and a velocity dispersion peak offset from the photometric center. Utilizing two independent methods-Schwarzschild orbit-superposition and Jeans Anisotropic Modeling-we tightly constrain the black hole mass by fitting the full line-of-sight velocity distribution. Our axisymmetric Schwarzschild models yield a best-fit black hole mass of $M_{BH} = 3.6^{+0.6}_{-0.6} \times 10^8 \, M_{\odot}$, slightly lower but significantly more precise than previous estimates. However, since our models do not account for the non-equilibrium nature of the double nucleus, this value may represent a lower limit. The inferred black hole mass corresponds to approximately 4-13% of the total stellar mass, providing robust evidence for an overmassive SMBH in NGC 4486B. Combined with the galaxy's location deep within the Virgo Cluster, our results support the interpretation that NGC 4486B is the tidally stripped remnant core of a formerly massive galaxy. As the JWST/NIRSpec field of view is insufficient to constrain the dark matter halo, we incorporate archival ground-based long-slit kinematics extending to 5 arcsec. While this provides some leverage on the dark matter content, the constraints remain relatively weak. We place only an upper limit on the dark matter fraction, with $M_{DM}/M_{*} < 0.5$ within 1 kpc-well beyond the effective radius. The inferred black hole mass remains unchanged with or without a dark matter halo.

A JWST View of the Overmassive Black Hole in NGC 4486B

Galaxy Evolution and AGN - Wed, 21/05/2025 - 10:36
arXiv:2505.14676v1 Announce Type: new Abstract: We present a new stellar dynamical measurement of the supermassive black hole (SMBH) in the compact elliptical galaxy NGC 4486B, based on integral field spectroscopy with JWST/NIRSpec. The two-dimensional kinematic maps reveal a resolved double nucleus and a velocity dispersion peak offset from the photometric center. Utilizing two independent methods-Schwarzschild orbit-superposition and Jeans Anisotropic Modeling-we tightly constrain the black hole mass by fitting the full line-of-sight velocity distribution. Our axisymmetric Schwarzschild models yield a best-fit black hole mass of $M_{BH} = 3.6^{+0.6}_{-0.6} \times 10^8 \, M_{\odot}$, slightly lower but significantly more precise than previous estimates. However, since our models do not account for the non-equilibrium nature of the double nucleus, this value may represent a lower limit. The inferred black hole mass corresponds to approximately 4-13% of the total stellar mass, providing robust evidence for an overmassive SMBH in NGC 4486B. Combined with the galaxy's location deep within the Virgo Cluster, our results support the interpretation that NGC 4486B is the tidally stripped remnant core of a formerly massive galaxy. As the JWST/NIRSpec field of view is insufficient to constrain the dark matter halo, we incorporate archival ground-based long-slit kinematics extending to 5 arcsec. While this provides some leverage on the dark matter content, the constraints remain relatively weak. We place only an upper limit on the dark matter fraction, with $M_{DM}/M_{*} < 0.5$ within 1 kpc-well beyond the effective radius. The inferred black hole mass remains unchanged with or without a dark matter halo.

INSPIRE: INvestigating Stellar Populations In RElics. IX. KiDS J0842+0059: the first fully confirmed relic beyond the local Universe

Galaxy Evolution and AGN - Wed, 21/05/2025 - 10:14
arXiv:2505.13611v1 Announce Type: new Abstract: Relics are massive, compact and quiescent galaxies that assembled the majority of their stars in the early Universe and lived untouched until today, completely missing any subsequent size-growth caused by mergers and interactions. They provide the unique opportunity to put constraints on the first phase of mass assembly in the Universe with the ease of being nearby. While only a few relics have been found in the local Universe, the {\tt INSPIRE} project has confirmed 38 relics at higher redshifts ($z \sim 0.2-0.4$), fully characterising their integrated kinematics and stellar populations. However, given the very small sizes of these objects and the limitations imposed by the atmosphere, structural parameters inferred from ground-based optical imaging are possibly affected by systematic effects that are difficult to quantify. In this paper, we present the first high-resolution image obtained with Adaptive Optics Ks-band observations on SOUL-LUCI@LBT of one of the most extreme {\tt INSPIRE} relics, KiDS~J0842+0059 at $z \sim 0.3$. We confirm the disky morphology of this galaxy (axis ratio of $0.24$) and its compact nature (circularized effective radius of $\sim 1$ kpc) by modelling its 2D surface brightness profile with a PSF-convolved S\'ersic model. We demonstrate that the surface mass density profile of KiDS~J0842+0059 closely resembles that of the most extreme local relic, NGC~1277, as well as of high-redshift red nuggets. We unambiguously conclude that this object is a remnant of a high-redshift compact and massive galaxy, which assembled all of its mass at $z>2$, and completely missed the merger phase of the galaxy evolution.

INSPIRE: INvestigating Stellar Populations In RElics. IX. KiDS J0842+0059: the first fully confirmed relic beyond the local Universe

Recent IoA Publications - Wed, 21/05/2025 - 10:14
arXiv:2505.13611v1 Announce Type: new Abstract: Relics are massive, compact and quiescent galaxies that assembled the majority of their stars in the early Universe and lived untouched until today, completely missing any subsequent size-growth caused by mergers and interactions. They provide the unique opportunity to put constraints on the first phase of mass assembly in the Universe with the ease of being nearby. While only a few relics have been found in the local Universe, the {\tt INSPIRE} project has confirmed 38 relics at higher redshifts ($z \sim 0.2-0.4$), fully characterising their integrated kinematics and stellar populations. However, given the very small sizes of these objects and the limitations imposed by the atmosphere, structural parameters inferred from ground-based optical imaging are possibly affected by systematic effects that are difficult to quantify. In this paper, we present the first high-resolution image obtained with Adaptive Optics Ks-band observations on SOUL-LUCI@LBT of one of the most extreme {\tt INSPIRE} relics, KiDS~J0842+0059 at $z \sim 0.3$. We confirm the disky morphology of this galaxy (axis ratio of $0.24$) and its compact nature (circularized effective radius of $\sim 1$ kpc) by modelling its 2D surface brightness profile with a PSF-convolved S\'ersic model. We demonstrate that the surface mass density profile of KiDS~J0842+0059 closely resembles that of the most extreme local relic, NGC~1277, as well as of high-redshift red nuggets. We unambiguously conclude that this object is a remnant of a high-redshift compact and massive galaxy, which assembled all of its mass at $z>2$, and completely missed the merger phase of the galaxy evolution.

Hubble Images Galaxies Near and Far

Astronomy News - Wed, 21/05/2025 - 09:59
Explore Hubble

2 min read

Hubble Images Galaxies Near and Far This NASA/ESA Hubble Space Telescope image features the remote galaxy HerS 020941.1+001557, which appears as a red arc that partially encircles a foreground elliptical galaxy. ESA/Hubble & NASA, H. Nayyeri, L. Marchetti, J. Lowenthal

This NASA/ESA Hubble Space Telescope image offers us the chance to see a distant galaxy now some 19.5 billion light-years from Earth (but appearing as it did around 11 billion years ago, when the galaxy was 5.5 billion light-years away and began its trek to us through expanding space). Known as HerS 020941.1+001557, this remote galaxy appears as a red arc partially encircling a foreground elliptical galaxy located some 2.7 billion light-years away. Called SDSS J020941.27+001558.4, the elliptical galaxy appears as a bright dot at the center of the image with a broad haze of stars outward from its core. A third galaxy, called SDSS J020941.23+001600.7, seems to be intersecting part of the curving, red crescent of light created by the distant galaxy.

The alignment of this trio of galaxies creates a type of gravitational lens called an Einstein ring. Gravitational lenses occur when light from a very distant object bends (or is ‘lensed’) around a massive (or ‘lensing’) object located between us and the distant lensed galaxy. When the lensed object and the lensing object align, they create an Einstein ring. Einstein rings can appear as a full or partial circle of light around the foreground lensing object, depending on how precise the alignment is. The effects of this phenomenon are much too subtle to see on a local level but can become clearly observable when dealing with curvatures of light on enormous, astronomical scales.

Gravitational lenses not only bend and distort light from distant objects but magnify it as well. Here we see light from a distant galaxy following the curve of spacetime created by the elliptical galaxy’s mass. As the distant galaxy’s light passes through the gravitational lens, it is magnified and bent into a partial ring around the foreground galaxy, creating a distinctive Einstein ring shape.

The partial Einstein ring in this image is not only beautiful, but noteworthy. A citizen scientist identified this Einstein ring as part of the SPACE WARPS project that asked citizen scientists to search for gravitational lenses in images.

Text Credit: ESA/Hubble

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Media Contact:

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

Share Details Last Updated May 20, 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.


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Focusing in on Gravitational Lenses


Hubble’s Night Sky Challenge

Telescope team reads the fine print — from more than a kilometre away

Astronomy News - Wed, 21/05/2025 - 09:56

Nature, Published online: 20 May 2025; doi:10.1038/d41586-025-01536-8

A pair of telescopes picking up reflected light achieve a performance 14 times better than a single telescope can manage alone.

Astronomers double down on claim of strongest evidence for alien life

Astronomy News - Wed, 21/05/2025 - 09:55

Are there aliens living on the exoplanet K2-18b? Some astronomers believe they have evidence for molecules on the planet that must have a biological origin, but others disagree

Ancient Maltese temples may have been schools for celestial navigation

Astronomy News - Wed, 21/05/2025 - 09:55

The alignment of some megalithic temples in Malta suggests they may have been used to teach sailors how to navigate by the stars

Earliest galaxy ever seen offers glimpse of the nascent universe

Astronomy News - Wed, 21/05/2025 - 09:54

The galaxy MoM-z14 dates back to 280 million years after the big bang, and the prevalence of such early galaxies is puzzling astronomers

Thu 22 May 11:30: Baryon Acoustic Oscillations from a Different Angle KICC Special Seminar

IoA Institute of Astronomy Talk Lists - Wed, 21/05/2025 - 08:30
Baryon Acoustic Oscillations from a Different Angle

The Dark Energy Spectroscopic Instrument (DESI) has published BAO measurements from one year of data (DR1) in 2024 and 3 years of data (DR2) in 2025. The DESI collaboration argue that their measurements suggest that dark energy is evolving and that this evidence is stronger using the DR2 data. This result would have major implications for fundamental physics if true. I will present a new way of looking at BAO data which shows that the DR2 data are more consistent with the Planck LCDM cosmology than the DR1 data. The evidence for evolving dark energy from DESI BAO has therefore weakened as the data have improved. I will also discuss the impact of systematic errors if DESI BAO data are combined with Type Ia supernovae. In summary, I find very little evidence to suggest that dark energy is evolving.

KICC Special Seminar

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Connecting JWST discovered N/O-enhanced galaxies to globular clusters: Evidence from chemical imprints

Galaxy Evolution and AGN - Tue, 20/05/2025 - 10:46
arXiv:2505.12505v1 Announce Type: new Abstract: Recent JWST observations have revealed a growing population of galaxies at $z>4$ with elevated nitrogen-to-oxygen ratios. These "N/O-enhanced" galaxies (NOEGs) exhibit near- to super-solar N/O at sub-solar O/H, clearly deviating from the well-established scaling relation between N/O and O/H observed in local galaxies. The origin of this abundance anomaly is unclear. Interestingly, local globular clusters also exhibit anomalous light-element abundances, whose origin remains debated. In this work, we compare the chemical abundance patterns of 22 known NOEGs at $0\lesssim z\lesssim 12$ -- primarily discovered with JWST -- to those observed in local globular clusters. We find striking similarities in the abundances of C, N, O, Fe, and He between the two populations. The similar abundance patterns support the scenario in which globular cluster stars formed within proto-cluster environments -- similar to those traced by NOEGs -- that were self-enriched. Indeed, the enhancement in N/O in early galaxies appears to be only found in dense stellar environments with $\Sigma _{\star}\gtrsim 10^{2.5}~M_\odot~{\rm pc^{-2}}$, as expected for the progenitors of globular clusters in the Milky Way, and similar to those of star clusters identified in strongly lensed high-redshift galaxies. Furthermore, we find a tentative positive correlation between N/O ratios and stellar mass among NOEGs. The apparent high occurrence rate of NOEGs at high redshift is consistent with the picture of cluster-dominated star formation during the early stages of galaxy evolution. Measuring chemical abundances across diverse stellar environments in high-redshift galaxies will be crucial for elucidating the connection between NOEGs and globular clusters.

Connecting JWST discovered N/O-enhanced galaxies to globular clusters: Evidence from chemical imprints

Recent IoA Publications - Tue, 20/05/2025 - 10:46
arXiv:2505.12505v1 Announce Type: new Abstract: Recent JWST observations have revealed a growing population of galaxies at $z>4$ with elevated nitrogen-to-oxygen ratios. These "N/O-enhanced" galaxies (NOEGs) exhibit near- to super-solar N/O at sub-solar O/H, clearly deviating from the well-established scaling relation between N/O and O/H observed in local galaxies. The origin of this abundance anomaly is unclear. Interestingly, local globular clusters also exhibit anomalous light-element abundances, whose origin remains debated. In this work, we compare the chemical abundance patterns of 22 known NOEGs at $0\lesssim z\lesssim 12$ -- primarily discovered with JWST -- to those observed in local globular clusters. We find striking similarities in the abundances of C, N, O, Fe, and He between the two populations. The similar abundance patterns support the scenario in which globular cluster stars formed within proto-cluster environments -- similar to those traced by NOEGs -- that were self-enriched. Indeed, the enhancement in N/O in early galaxies appears to be only found in dense stellar environments with $\Sigma _{\star}\gtrsim 10^{2.5}~M_\odot~{\rm pc^{-2}}$, as expected for the progenitors of globular clusters in the Milky Way, and similar to those of star clusters identified in strongly lensed high-redshift galaxies. Furthermore, we find a tentative positive correlation between N/O ratios and stellar mass among NOEGs. The apparent high occurrence rate of NOEGs at high redshift is consistent with the picture of cluster-dominated star formation during the early stages of galaxy evolution. Measuring chemical abundances across diverse stellar environments in high-redshift galaxies will be crucial for elucidating the connection between NOEGs and globular clusters.

Nearby stellar substructures in the Galactic halo from DESI Milky Way Survey Year 1 Data Release

Recent IoA Publications - Tue, 20/05/2025 - 10:36
arXiv:2504.20327v2 Announce Type: replace Abstract: We report five nearby ($d_{\mathrm{helio}} < 5$ kpc) stellar substructures in the Galactic halo from a subset of 138,661 stars in the Dark Energy Spectroscopic Instrument (DESI) Milky Way Survey Year 1 Data Release. With an unsupervised clustering algorithm, HDBSCAN*, these substructures are independently identified in Integrals of Motion ($E_{\mathrm{tot}}$, $L_{\mathrm z}$, $\log{J_r}$, $\log{J_z}$) space and Galactocentric cylindrical velocity space ($V_{R}$, $V_{\phi}$, $V_{z}$). We associate all identified clusters with known nearby substructures (Helmi streams, M18-Cand10/MMH-1, Sequoia, Antaeus, and ED-2) previously reported in various studies. With metallicities precisely measured by DESI, we confirm that the Helmi streams, M18-Cand10, and ED-2 are chemically distinct from local halo stars. We have characterised the chemodynamic properties of each dynamic group, including their metallicity dispersions, to associate them with their progenitor types (globular cluster or dwarf galaxy). Our approach for searching substructures with HDBSCAN* reliably detects real substructures in the Galactic halo, suggesting that applying the same method can lead to the discovery of new substructures in future DESI data. With more stars from future DESI data releases and improved astrometry from the upcoming Gaia Data Release 4, we will have a more detailed blueprint of the Galactic halo, offering a significant improvement in our understanding of the formation and evolutionary history of the Milky Way Galaxy.