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Almost all moon landers break down during the extraordinary cold of lunar night, but Japan’s Smart Lander for Investigating Moon has astonishingly survived three nights

Scientists from the Cambridge University have suggested that molecules vital to the development of life could have formed from a process known as graphitisation. Once verified in the laboratory, the finding could allow scientists to recreate plausible conditions for life's emergence. It has long been debated how the...

TBC

Details to be confirmed

• Speaker: Blake Sherwin (DAMTP)
• Tuesday 25 June 2024, 11:30-12:30
• Venue: Hoyle Lecture Theatre and online (details to be sent by e-mail).
• Series: New Frontiers in Astrophysics: A KICC Perspective; organiser: Steven Brereton.

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TBC

Details to be confirmed

• Speaker: Blake Sherwin (DAMTP)
• Tuesday 25 June 2024, 11:30-12:30
• Venue: Hoyle Lecture Theatre and online (details to be sent by e-mail).
• Series: New Frontiers in Astrophysics: A KICC Perspective; organiser: Steven Brereton.

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Radio observations of extra-galactic transients with the AMI-LA telescope

The Arcminute Microkelvin Imager – Large Array has been instrumental in the study of radio transients. In this talk I will give an overview of the current extragalactic transients monitoring program which is running on AMI -LA. To demonstrate the power of AMI -LA in improving our shock physics in extragalactic transients I will go through two examples of events where AMI -LA has been instrumental. Starting with the most relativistic systems: GRBs have been observed by AMI -LA from as early as 2012 with the ALARRM rapid follow up system. GRB 221009A , also known as the brightest of all time, has demonstrated the unparalleled temporal coverage achievable with AMI -LA from a few hours to over 100 days post burst. AMI -LA has also enabled us to draw conclusions that wouldn’t be possible with other facilities such as the jetted tidal disruption event AT2022cmc that was first reported in 2022. Due to the high cadence light curve with AMI -LA, we were able to prove for the first time, in a model independent manner that the radio emission originated from a highly relativistic outflow. Such a result has been vital in terms of our understand of tidal disruption events and can now infer the presence of off-axis jets such as AT2018hyz.

• Speaker: Dr. Lauren Rhodes (University of Oxford)
• Tuesday 30 April 2024, 11:15-12:00
• Venue: Coffee area, Battcock Centre.
• Series: Hills Coffee Talks; organiser: Charles Walker.

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Cosmology from Non-Gaussian fields

In this talk I will discuss several challenges towards detecting primordial non-Gaussianties. With the CMB running out of modes, we have started focussing on large scale structure. Measurements of the 21cm brightness temperature allow us to observe almost our entire past light cone. Based on comoving volume arguments, the epoch starting during the dark ages and ending the epoch of reionzation (EoR) potentially contain a lot of modes. Besides being hard to detect, even at these high redshifts, when modes were more linear, I will argue both signal confusion and non-Gaussian covariance have to be considered. During the EoR, the tracer field is very non-Gaussian and standard summary statistics might no longer suffice. I will discuss how machine learning could help solving some of these challenges, while also benefiting efforts to understand astrophysical evolution during these epochs. Finally, ML applications in cosmology are rapidly developing. We should remain cautious and apply common sense. I will discuss an example of what could happen if we don’t.

• Speaker: Daan Meerburg (University of Groningen)
• Monday 29 April 2024, 13:00-14:00
• Venue: CMS, Pav. B, CTC Common Room (B1.19) [Potter Room].
• Series: Cosmology Lunch; organiser: Fiona McCarthy.

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arXiv:2402.18624v2 Announce Type: replace Abstract: We use rest-frame optical and near-infrared (NIR) observations of 42 Type Ia supernovae (SNe Ia) from the Carnegie Supernova Project at low-$z$ and 37 from the RAISIN Survey at high-$z$ to investigate correlations between SN Ia host galaxy dust, host mass, and redshift. This is the first time the SN Ia host galaxy dust extinction law at high-$z$ has been estimated using combined optical and rest-frame NIR data ($YJ$-band). We use the BayeSN hierarchical model to leverage the data's wide rest-frame wavelength range (extending to $\sim$1.0-1.2 microns for the RAISIN sample at $0.2\lesssim z\lesssim0.6$). By contrasting the RAISIN and CSP data, we constrain the population distributions of the host dust $R_V$ parameter for both redshift ranges. We place a limit on the difference in population mean $R_V$ between RAISIN and CSP of $-1.16

Title to be confirmed

Abstract not available

• Speaker: Sergio Martin Alvarez (Stanford)
• Thursday 13 June 2024, 11:30-12:30
• Venue: Ryle seminar room + online.
• Series: Galaxies Discussion Group; organiser: Sandro Tacchella.

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In celebration of the 34th anniversary of the launch of NASA’s Hubble Space Telescope, astronomers took a snapshot of the Little Dumbbell Nebula, also known as Messier 76, or M76, located 3,400 light-years away in the northern circumpolar constellation Perseus. The name ‘Little Dumbbell’ comes from its shape that is a two-lobed structure of colorful, mottled, glowing gases resembling a balloon that’s been pinched around a middle waist. Like an inflating balloon, the lobes are expanding into space from a dying star seen as a white dot in the center. Blistering ultraviolet radiation from the super-hot star is causing the gases to glow. The red color is from nitrogen, and blue is from oxygen.NASA, ESA, STScI

To celebrate the 34th anniversary of the Hubble Space Telescope’s launch, the telescope captured an image of the Little Dumbbell Nebula, or M76. M76 is a planetary nebula, an expanding shell of glowing gases that were ejected from a dying red giant star that eventually collapses to an ultra-dense and hot white dwarf. It gets its descriptive name from its shape: a ring, seen edge-on as the central bar structure, and two lobes on either opening of the ring.

Since its launch in 1990 Hubble has made 1.6 million observations of over 53,000 astronomical objects. Most of Hubble’s discoveries were not anticipated before launch, such as supermassive black holes, the atmospheres of exoplanets, gravitational lensing by dark matter, the presence of dark energy, and the abundance of planet formation among stars.

Learn more about the Little Dumbbell Nebula and Hubble.

Image Credit: NASA, ESA, STScI

arXiv:2404.14127v1 Announce Type: new Abstract: Gaia can not individually resolve very close binary systems, however, the collected data can still be used to identify them. A powerful indicator of stellar multiplicity is the sources reported Renormalized Unit Weight Error (ruwe), which effectively captures the astrometric deviations from single-source solutions. We aim to characterise the imprints left on ruwe caused by binarity. By flagging potential binary systems based on ruwe, we aim to characterise which of their properties will contribute the most to their detectability. We develop a model to estimate ruwe values for observations of Gaia sources, based on the biases to the single-source astrometric track arising from the presence of an unseen companion. Then, using the recipes from previous GaiaUnlimited selection functions, we estimate the selection probability of sources with high ruwe, and discuss what binary properties contribute to increasing the sources ruwe. We compute the maximum ruwe value which is compatible with single-source solutions as a function of their location on-sky. We see that binary systems selected as sources with a ruwe higher than this sky-varying threshold have a strong detectability window in their orbital period distribution, which peaks at periods equal to the Gaia observation time baseline. We demonstrate how our sky-varying ruwe threshold provides a more complete sample of binary systems when compared to single sky-averaged values by studying the unresolved binary population in the Gaia Catalogue of Nearby Stars. We provide the code and tools used in this study, as well as the sky-varying ruwe threshold through the GaiaUnlimited Python package

Nature, Published online: 22 April 2024; doi:10.1038/s41586-024-07412-1

Star Formation Shut Down by Multiphase Gas Outflow in a Galaxy at a Redshift of 2.45

Agencies and scientists from around the world head to the UK to share space-exploration techniques.

Nasa says its most distant probe is once again sending usable information back to Earth.

In a series of studies, a team of astronomers (including IoA postdoc Álvaro Ribas) has shed new light on the fascinating and complex process of planet formation. The stunning images, captured using the European Southern Observatory's Very Large Telescope (ESO’s VLT) in Chile, represent one of the largest ever surveys of...

Uniqueness of extremal black holes in de Sitter

Uniqueness theorems for black holes with a cosmological constant are only known in a few limited cases. In my talk I present a recent uniqueness theorem for the extremal Schwarzschild-de Sitter black hole within the class of analytic vacuum spacetimes with a positive cosmological constant containing a static extremal Killing horizon. The proof is based on establishing the uniqueness of transverse deformations to the near-horizon geometry at each order in the transverse parameter. I also present a generalisation to charged extremal black holes in de Sitter and discuss the analogous problem in the case of negative cosmological constant. The talk is based on 2309.04238 [gr-qc] and 2403.08467 [gr-qc].

• Speaker: Dávid Katona, The University of Edinburgh
• Friday 26 April 2024, 13:00-14:00
• Venue: Potter room/Zoom.
• Series: DAMTP Friday GR Seminar; organiser: Xi Tong.

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Neural ratio estimation: the future of supernova cosmology?

Simulation-based inference (SBI) has the potential to revolutionise how we do supernova cosmology and let us incorporate arbitrarily complex effects within a Bayesian model. I will present recent work which sought to validate neural ratio estimation (NRE) by comparing NRE -derived posteriors on supernova properties to those obtained with a likelihood-based MCMC approach for the same data, and then discuss how NRE and SBI in general provide a pathway towards a model extending all the way from type Ia supernova light curves to cosmological parameters as part of a single analysis.

• Speaker: Matthew Grayling (University of Cambridge)
• Wednesday 24 April 2024, 10:00-11:00
• Venue: Martin Ryle Seminar Room, KICC.
• Series: Astro Data Science Discussion Group; organiser: David Yallup.

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arXiv:2404.10486v2 Announce Type: replace Abstract: Gravitational waves from black-hole merging events have revealed a population of extra-galactic BHs residing in short-period binaries with masses that are higher than expected based on most stellar evolution models - and also higher than known stellar-origin black holes in our Galaxy. It has been proposed that those high-mass BHs are the remnants of massive metal-poor stars. Gaia astrometry is expected to uncover many Galactic wide-binary systems containing dormant BHs, which may not have been detected before. The study of this population will provide new information on the BH-mass distribution in binaries and shed light on their formation mechanisms and progenitors. As part of the validation efforts in preparation for the fourth Gaia data release (DR4), we analysed the preliminary astrometric binary solutions, obtained by the Gaia Non-Single Star pipeline, to verify their significance and to minimise false-detection rates in high-mass-function orbital solutions. The astrometric binary solution of one source, Gaia BH3, implies the presence of a 32.70 \pm 0.82 M\odot BH in a binary system with a period of 11.6 yr. Gaia radial velocities independently validate the astrometric orbit. Broad-band photometric and spectroscopic data show that the visible component is an old, very metal-poor giant of the Galactic halo, at a distance of 590 pc. The BH in the Gaia BH3 system is more massive than any other Galactic stellar-origin BH known thus far. The low metallicity of the star companion supports the scenario that metal-poor massive stars are progenitors of the high-mass BHs detected by gravitational-wave telescopes. The Galactic orbit of the system and its metallicity indicate that it might belong to the Sequoia halo substructure. Alternatively, and more plausibly, it could belong to the ED-2 stream, which likely originated from a globular cluster that had been disrupted by the Milky Way.

arXiv:2404.12585v1 Announce Type: new Abstract: The attenuation of Ly$\alpha$ photons by neutral hydrogen in the intergalactic medium (IGM) at $z\gtrsim5$ continues to be a powerful probe for studying the epoch of reionisation. Given a framework to estimate the intrinsic (true) Ly$\alpha$ emission of high-$z$ sources, one can infer the ionisation state of the IGM during reionisation. In this work, we use the enlarged XQR-30 sample of 42 high-resolution and high-SNR QSO spectra between $5.8\lesssim\,z\lesssim\,6.6$ obtained with VLT/X-Shooter to place constraints on the IGM neutral fraction. This is achieved using our existing Bayesian QSO reconstruction framework which accounts for uncertainties such as the: (i) posterior distribution of predicted intrinsic Ly$\alpha$ emission profiles (obtained via covariance matrix reconstruction of the Ly$\alpha$ and N V emission lines from unattenuated high-ionisation emission line profiles; C IV, Si IV + O IV] and C III]) and (ii) distribution of ionised regions within the IGM using synthetic damping wing profiles drawn from a $1.6^3$ Gpc$^3$ reionisation simulation. Following careful quality control, we used 23 of the 42 available QSOs to obtain constraints/limits on the IGM neutral fraction during the tail-end of reionisation. Our median and 68th percentile constraints on the IGM neutral fraction are: $0.20\substack{+0.14\\-0.12}$ and $0.29\substack{+0.14\\-0.13}$ at $z = 6.15$~and 6.35. Further, we also report 68th percentile upper-limits of $\bar{x}_{\mathrm{H\,{\scriptscriptstyle I}}}

The US space agency is seeking a cheaper, faster solution to bring Martian rocks to Earth for study.

An Australian bull ant is the first animal known to use the patterns produced by polarised moonlight to navigate its environment