skip to content
Home

Institute of Astronomy

 

Feed aggregator Subscribe to Institute of Astronomy aggregator

Tue 26 Nov 11:15: Results of beamline testing at the MROI

Next External Talks - Wed, 01/05/2024 - 11:14
Results of beamline testing at the MROI

TBC

Add to your calendar or Include in your list

Categories: Talks

Thu 13 Jun 16:00: Title to be confirmed

IoA Institute of Astronomy Talk Lists - Tue, 30/04/2024 - 17:01
Title to be confirmed

Abstract not available

Add to your calendar or Include in your list

Thu 13 Jun 16:00: Title to be confirmed

Next Colloquia - Tue, 30/04/2024 - 17:01
Title to be confirmed

Abstract not available

Add to your calendar or Include in your list

Categories: Talks

Thu 13 Jun 16:00: Title to be confirmed

IoA Institute of Astronomy Talk Lists - Tue, 30/04/2024 - 17:01
Title to be confirmed

Abstract not available

Add to your calendar or Include in your list

Thu 13 Jun 16:00: Title to be confirmed

Next Colloquia - Tue, 30/04/2024 - 17:01
Title to be confirmed

Abstract not available

Add to your calendar or Include in your list

Categories: Talks

Thu 09 May 16:00: Insights into cosmological simulations from modified initial conditions

IoA Institute of Astronomy Talk Lists - Tue, 30/04/2024 - 16:51
Insights into cosmological simulations from modified initial conditions

I will discuss the GMGalaxies programme, which is pursuing a new ‘hybrid’ approach to cosmological galaxy formation simulations combining the best of cosmological zooms and idealised approaches of the past. By customising (‘genetically modifying’) our initial conditions, we can construct controlled tests of structure formation within a fully cosmological environment. This approach has allowed us to obtain new and unique insights into ultra-faint dwarf galaxy formation, AGN -driven galaxy quenching, large scale structure formation and — in soon-to-be-released ultra-high-resolution simulations — the Milky Way fossil record seen by Gaia. In this talk, I will summarise some of these results but focus especially on recent insights into dwarf galaxy formation.

Add to your calendar or Include in your list

Thu 09 May 16:00: Insights into cosmological simulations from modified initial conditions

Next Colloquia - Tue, 30/04/2024 - 16:51
Insights into cosmological simulations from modified initial conditions

I will discuss the GMGalaxies programme, which is pursuing a new ‘hybrid’ approach to cosmological galaxy formation simulations combining the best of cosmological zooms and idealised approaches of the past. By customising (‘genetically modifying’) our initial conditions, we can construct controlled tests of structure formation within a fully cosmological environment. This approach has allowed us to obtain new and unique insights into ultra-faint dwarf galaxy formation, AGN -driven galaxy quenching, large scale structure formation and — in soon-to-be-released ultra-high-resolution simulations — the Milky Way fossil record seen by Gaia. In this talk, I will summarise some of these results but focus especially on recent insights into dwarf galaxy formation.

Add to your calendar or Include in your list

Categories: Talks

Thu 06 Jun 16:00: Black hole accretion in the TDAMM Era

IoA Institute of Astronomy Talk Lists - Tue, 30/04/2024 - 12:40
Black hole accretion in the TDAMM Era

Most of the power from an Active Galactic Nucleus is released close to the black hole, and thus studying accretion at event horizon scales—at the intersection of inflow and outflow—is essential for understanding how much matter accretes and grows the black hole vs. how much matter is ejected, thus effecting the black hole’s large-scale environments. In the past decade, we have had a breakthrough in how we probe the inner accretion flow, through the discovery of X-ray Reverberation Mapping, where X-rays produced close to the black hole reverberate off inflowing gas. By measuring reverberation time delays, we can quantify the effects of strongly curved space time and measure black hole spin, which is key for understanding how efficiently energy can be tapped from the accretion process. In this talk, I will give an overview of this field, and will show how extending these spectral-timing techniques to extreme, transient (and possibly multi-messenger) accretion events like Tidal Disruption Events and Quasi Periodic Eruptions can help us understand the growth and impact of black holes in galactic centers.

Add to your calendar or Include in your list

Thu 06 Jun 16:00: Black hole accretion in the TDAMM Era

Next Colloquia - Tue, 30/04/2024 - 12:40
Black hole accretion in the TDAMM Era

Most of the power from an Active Galactic Nucleus is released close to the black hole, and thus studying accretion at event horizon scales—at the intersection of inflow and outflow—is essential for understanding how much matter accretes and grows the black hole vs. how much matter is ejected, thus effecting the black hole’s large-scale environments. In the past decade, we have had a breakthrough in how we probe the inner accretion flow, through the discovery of X-ray Reverberation Mapping, where X-rays produced close to the black hole reverberate off inflowing gas. By measuring reverberation time delays, we can quantify the effects of strongly curved space time and measure black hole spin, which is key for understanding how efficiently energy can be tapped from the accretion process. In this talk, I will give an overview of this field, and will show how extending these spectral-timing techniques to extreme, transient (and possibly multi-messenger) accretion events like Tidal Disruption Events and Quasi Periodic Eruptions can help us understand the growth and impact of black holes in galactic centers.

Add to your calendar or Include in your list

Categories: Talks

Fri 05 Jul 11:30: Title to be confirmed

IoA Institute of Astronomy Talk Lists - Tue, 30/04/2024 - 10:26
Title to be confirmed

Abstract not available

Add to your calendar or Include in your list

What China’s mission to collect rocks from the far side could reveal about the Moon

Astronomy News - Tue, 30/04/2024 - 08:32

Nature, Published online: 30 April 2024; doi:10.1038/d41586-024-01056-x

The Chang’e-6 mission aims to land in the Moon’s oldest and largest crater, collect rocks, and bring them back to Earth.

The Horse’s Mane

Astronomy News - Tue, 30/04/2024 - 08:31
Rising from turbulent waves of dust and gas is the Horsehead Nebula, otherwise known as Barnard 33, which resides roughly 1300 light-years away. The NASA/ESA/CSA James Webb Space Telescope has captured the sharpest infrared images to date of one of the most distinctive objects in our skies, the Horsehead Nebula. Webb’s new view focuses on the illuminated edge of the top of the nebula’s distinctive dust and gas structure.

This image of part of the Horsehead Nebula, captured by NASA’s James Webb Space Telescope and released on April 29, 2024, shows the nebula in a whole new light, capturing the region’s complexity with unprecedented spatial resolution. Located roughly 1,300 light-years away, the nebula formed from a collapsing interstellar cloud of material, and glows because it is illuminated by a nearby hot star. The gas clouds surrounding the Horsehead have already dissipated, but the jutting pillar is made of thick clumps of material and therefore is harder to erode. Astronomers estimate that the Horsehead has about 5 million years left before it too disintegrates.

Image Credit: NASA, ESA, CSA, K. Misselt (University of Arizona) and A. Abergel (IAS/University Paris-Saclay, CNRS)

UN Women Executive Director Visits ESO in Chile and Reinforces STEM Collaboration

Astronomy News - Tue, 30/04/2024 - 08:28

On Monday, April 29th, a delegation from UN Women, an organisation dedicated to gender equality and the empowerment of women, visited the European Southern Observatory (ESO) offices in Santiago, Chile, to further advance the inclusion of women in astronomical observatories and Science, technology, engineering, and mathematics (STEM) disciplines.

The delegation, headed by Sima Sami Bahous, UN Women's Executive Director, and María Noel Vaeza, UN Women's Regional Director for the Americas and the Caribbean, was received by Bárbara Nuñez, ESO Regional Relations Officer and Luis Chavarría, ESO Representative in Chile. Bahous also met virtually with Xavier Barcons, ESO Director General, and part of the team of the Chilean Non-Governmental Organisation Ingeniosas, which promotes and supports the inclusion of young girls into STEM fields.

During the meeting, the delegations discussed the outcomes of the Memorandum of Understanding between ESO and UN Women, signed in 2020 and renewed earlier this year. This collaboration aims to promote science and engineering among girls and adolescents, empower marginalised women in Chile through training and education, and advocate for adopting and implementing the Women Empowerment Principles.

In 2021, ESO and UN Women launched a training program focused on telescope optical maintenance for professional astronomical observatories, targeting women in the Antofagasta Region. This initiative enhanced women's technical skills and increased job opportunities in traditionally male-dominated fields. Following a selection process, three participants were hired by ESO through the LINKES contractor and are now employed in operations at ESO’s Paranal Observatory.

​​Over the next three years, ESO and UN Women will replicate this successful program with young girls and women from Antofagasta technical schools, focusing on underprivileged communities. Additionally, they will collaborate with educational institutions and students to encourage women to pursue educational and employment opportunities in STEM while also working to eliminate gender stereotypes.

Fri 03 May 13:00: Black Hole Entropy for Higher Curvature Gravity with Higher Spin Fields

Next External Talks - Mon, 29/04/2024 - 17:48
Black Hole Entropy for Higher Curvature Gravity with Higher Spin Fields

Assuming a Killing horizon background, we generalise the linear null Raychaudhuri equation to higher curvature gravity with spin s ≥ 2 bosonic fields, and we attempt to extract the black hole entropy from the Raychaudhuri equation at the linear order of dynamical perturbation. Unlike pure gravity, scalar fields, and vector fields, we show that an additional “integrability condition” must be satisfied by the higher spin theory/field in order to extract a “sensible” entropy formula. We test this condition in several examples and speculate about its role for higher spin theories.

Add to your calendar or Include in your list

Categories: Talks

Mon 20 May 14:00: Title to be confirmed

Next External Talks - Mon, 29/04/2024 - 17:22
Title to be confirmed

Abstract not available

Add to your calendar or Include in your list

Categories: Talks

Tue 21 May 14:00: Title to be confirmed

Next External Talks - Mon, 29/04/2024 - 17:19
Title to be confirmed

Abstract not available

Add to your calendar or Include in your list

Categories: Talks

Tue 14 May 11:15: Blue Phase Liquid Crystals & Their Potential for Astronomy

Next External Talks - Mon, 29/04/2024 - 14:53
Blue Phase Liquid Crystals & Their Potential for Astronomy

Adaptive optics is a technique used to reduce the effects of aberration on wavefront propagation, used to correct for the light distortion which appears due to atmospheric turbulence. Customarily, in astronomy, systems employed for this purpose use deformable or adaptive mirrors as correctors, which are costly and mechanically actuated.

As opposed to a classic deformable mirror, which requires actuators to change its shape, a Liquid Crystal Wavefront Corrector (LCWFC) uses its inherent birefringence to act as a phase modulator and correct the incoming wavefront. Despite its reduced size and cost, LCWF Cs have historically suffered from a large response time, which makes them less desirable over typical solutions.

Blue Phases will be introduced as an alternative correcting medium. They have the potential to overcome the usual limitations of liquid crystal devices. Their working principle and typical design considerations will be presented, as well as progress made in making these devices a reality.

Add to your calendar or Include in your list

Categories: Talks

Tue 28 May 13:00: Title to be confirmed

Next External Talks - Mon, 29/04/2024 - 11:47
Title to be confirmed

TBA

Add to your calendar or Include in your list

Categories: Talks

A JWST Medium Resolution MIRI Spectrum and Models of the Type Ia supernova 2021aefx at +415 d

Recent IoA Publications - Mon, 29/04/2024 - 09:22
arXiv:2404.17043v1 Announce Type: new Abstract: We present a JWST MIRI/MRS spectrum (5-27 $\mathrm{\mu}$m) of the Type Ia supernova (SN Ia), SN 2021aefx at $+415$ days past $B$-band maximum. The spectrum, which was obtained during the iron-dominated nebular phase, has been analyzed in combination with previous JWST observations of SN 2021aefx, to provide the first JWST time series analysis of an SN Ia. We find the temporal evolution of the [Co III] 11.888 $\mathrm{\mu}$m feature directly traces the decay of $^{56}$Co. The spectra, line profiles, and their evolution are analyzed with off-center delayed-detonation models. Best fits were obtained with White Dwarf (WD) central densities of $\rho_c=0.9-1.1\times 10^9$g cm$^{-3}$, a WD mass of M$_{\mathrm{WD}}$=1.33-1.35M$_\odot$, a WD magnetic field of $\approx10^6$G, and an off-center deflagration-to-detonation transition at $\approx$ 0.5 $M_\odot$ seen opposite to the line of sight of the observer. The inner electron capture core is dominated by energy deposition from $\gamma$-rays whereas a broader region is dominated by positron deposition, placing SN 2021aefx at +415 d in the transitional phase of the evolution to the positron-dominated regime. The formerly `flat-tilted' profile at 9 $\mathrm{\mu}$m now has significant contribution from [Ni IV], [Fe II], and [Fe III] and less from [Ar III], which alters the shape of the feature as positrons excite mostly the low-velocity Ar. Overall, the strength of the stable Ni features in the spectrum is dominated by positron transport rather than the Ni mass. Based on multi-dimensional models, our analysis strongly supports a single-spot, close-to-central ignition with an indication for a pre-existing turbulent velocity field, and excludes a multiple-spot, off-center ignition.

Wed 01 May 14:00: Resolution: New Insights from Modular Symmetry in Conformal Field Theory

Next External Talks - Mon, 29/04/2024 - 01:04
Resolution: New Insights from Modular Symmetry in Conformal Field Theory

I will explain how tools from the theory of modular forms may be used to resolve operator spectra of conformal field theories. This leads to a quantitative framework for diagnosing quantum chaos and random matrix behavior in field theory and gravity.

Add to your calendar or Include in your list

Categories: Talks

User login

Study at Cambridge

About the University

Research at Cambridge