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NASA Volunteers Find Fifteen Rare “Active Asteroids”

Astronomy News - Sat, 16/03/2024 - 15:12
2 Min Read NASA Volunteers Find Fifteen Rare “Active Asteroids” NASA’s Active Asteroids project Credits:
Henry Hsieh

Some extraordinary asteroids have “activity”—comet-like tails or envelopes of gas and dust.  NASA’s Active Asteroids project announced the discovery of activity on fifteen asteroids, challenging conventional wisdom about the solar system.

To find these fifteen rare objects, more than 8000 volunteers combed through 430,000 images from the Dark Energy Camera (DECam) on the Victor M. Blanco telescope in Chile. A paper about the results, now published in the Astronomical Journal, includes nine volunteers among the co-authors.

“For an amateur astronomer like me it’s a dream come true.” said volunteer Virgilio Gonano from Udine, Italy. “Congratulations to all the staff and the friends that also check the images!”

Volunteers from the NASA’s “Active Asteroids” Citizen Science project identified a comet tail coming from
Asteroid 2015 VA108, one of the active asteroids spotted by volunteers from NASA’s “Active Asteroids” Citizen Science project. The object, indicated by the green arrow, orbits entirely within the main asteroid belt (located between Mars and Jupiter), but sports a tail like a comet. Credit: Colin Orion Chandler (University of Washington)

Studying these rare active asteroids teaches scientists about the formation and evolution of the solar system, including the origins of water here on Earth. These objects may also aid future space exploration because the same ices that cause comet-like tails can power rockets or provide breathable air.

“I have been a member of the Active Asteroids team since its first batch of data,” said volunteer Tiffany Shaw-Diaz from Dayton, Ohio. “And to say that this project has become a significant part of my life is an understatement. I look forward to classifying subjects each day, as long as time or health permits, and I am beyond honored to work with such esteemed scientists on a regular basis.”

The Active Asteroids project was founded by Dr. Colin Orion Chandler, a LINCC Frameworks project scientist at the University of Washington and DiRAC Institute.  To join the project and help discover the next active asteroid, visit https://www.activeasteroids.net.

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Perfectly straight ridges may cover the poles of Saturn’s moon Titan

Astronomy News - Sat, 16/03/2024 - 15:11

Saturn’s moon Titan may have hundreds of strange ridges called yardangs that could teach us how the icy moon’s geology and conditions vary across its surface

Brightest and hungriest black hole ever detected

Astronomy News - Fri, 15/03/2024 - 12:55

Astronomers report an object that shines with a brightness equivalent to 500 trillion suns.

The moons of Mars may have been formed in an icy planetary collision

Astronomy News - Fri, 15/03/2024 - 12:43

The origins of Mars’s moons Phobos and Deimos have long been an enigma, but they may have been formed when a icy, comet-like object slammed into the Red Planet

Mars's gravitational pull may be strong enough to stir Earth's oceans

Astronomy News - Fri, 15/03/2024 - 12:43

An analysis of deep-sea drill cores suggests that Mars may have enough gravitational influence to shift sediment within Earth's oceans on a 2.4-million-year cycle

The surprising ways animals react to a total solar eclipse

Astronomy News - Fri, 15/03/2024 - 12:43

When the moon hides the sun in a total solar eclipse, some animals seem to think that it is briefly nighttime, while others pace anxiously or even gaze up at the sky

Sleeping black hole is way more massive than it should be

Astronomy News - Fri, 15/03/2024 - 12:42

The James Webb Space Telescope has found an unusual galaxy in the early universe with a black hole almost half the mass of the galaxy itself, raising questions about how it formed

Rethinking space and time could let us do away with dark matter

Astronomy News - Fri, 15/03/2024 - 12:42

Most physicists believe that only a quantum theory of gravity can fully explain mysteries of the universe like dark matter, but now an idea called "post-quantum gravity" is demonstrating an alternative approach

Europa’s seafloor may be impenetrable and inhospitable to life

Astronomy News - Fri, 15/03/2024 - 12:42

The seafloor of Jupiter’s icy moon Europa was thought to provide energy and nutrients to its ocean, but it turns out that may not be possible

A single meteorite smashed into Mars and created 2 billion craters

Astronomy News - Fri, 15/03/2024 - 12:41

The debris from the formation of a relatively small crater on Mars created billions of additional craters, which could help us learn about Martian geology

First segments of world’s largest telescope mirror have a shiny new surface

Astronomy News - Fri, 15/03/2024 - 12:05

The construction of ESO’s Extremely Large Telescope (ELT) in the Chilean Atacama Desert has reached a new milestone: a team at ESO’s Paranal Observatory have added a reflective, shiny layer, as well as special sensors, to the first segments of the telescope’s primary mirror. This “coating” means the segments are now essentially ready to start observing the skies, once installed at the heart of the world’s largest optical telescope later this decade. 

The 39-metre primary mirror of ESO’s ELT, known as M1, will be by far the largest mirror ever made for a telescope. Too large to be made from a single piece of glass, it will consist of 798 glass-ceramic hexagonal segments, each about five centimetres thick and 1.5 metres across. The mirror segments are manufactured in Europe in a multi-step, multinational process. The first 18 made their way across the ocean to Paranal earlier this year, and coating is the next step on their journey — a milestone that three segments have now reached. 

Coating an M1 mirror segment is a complex process that takes about two hours. In addition to a reflective layer, which uses 1.7 grams of silver, the coating includes additional layers of nickel chromium and silicon nitride to improve adhesion to the mirror blank and protect the silver from tarnishing. Overall, the coating is around 120 nanometres thick, or about one thousand times thinner than a human hair. 

To make sure that all segments can work together as a single mirror, they are equipped with sensors to detect misalignments. Besides adding a coating to the first M1 segments, ESO engineers have also installed these so-called edge sensors, two per side of each segment, and integrated the electronics and mechanical supports needed for them to work. Finally, they have performed inspections and health checks to ensure that the segments are ready to be installed on ESO’s ELT. The entire process takes place inside a ‘clean room’ — where the number of particles in the air is carefully controlled to avoid contamination — in the ELT Technical Facility in Paranal. 

The coating and integration procedures will be repeated for all other M1 segments. Meticulously testing and documenting the process for the first three segments was therefore key to ensure the operation can be ramped-up once new segments arrive at Paranal. 

Once the telescope is operational, the coating process will be repeated on each segment every 18 months, to ensure the best reflectivity and sensitivity. In practice, this means that two segments will need to be recoated every day for the entire lifetime of the telescope. To facilitate this with minimal disruption to the scientific observations, an extra 133 segments are being manufactured, in addition to the 798 needed for the mirror. The world’s biggest eye on the sky is poised to tackle the most profound astronomical challenges of our time, promising groundbreaking discoveries once it sees first light later this decade.

cosmocnc: A fast, flexible, and accurate galaxy cluster number, count likelihood code for cosmology

Recent IoA Publications - Fri, 15/03/2024 - 10:56
arXiv:2403.09589v1 Announce Type: new Abstract: We introduce cosmocnc, a Python package for computing the number count likelihood of galaxy cluster catalogues in a fast, flexible and accurate way. cosmocnc offers three types of likelihoods: an unbinned, a binned, and an extreme value likelihood. It also supports the addition of stacked cluster data, which is modelled consistently with the cluster catalogue. The unbinned likelihood, which is the main focus of the code, can take an arbitrary number of mass observables as input and deal with several complexities in the data, such as variations in the properties of the cluster observable across the survey footprint, the possibility of different clusters having measurements for different combinations of mass observables, redshift measurement uncertainties, and the presence on unconfirmed detections in the catalogue. If there are more than one mass observables, the unbinned likelihood is computed with the backward convolutional approach, a novel approach that is first implemented in cosmocnc. After developing the likelihood formalism and describing its implementation, we validate the code with synthetic Simons-Observatory-like catalogues, finding excellent agreement between their properties and cosmocnc's predictions and obtaining constraints on cosmological and scaling relation parameters featuring negligible biases. cosmocnc is publicly available at github.com/inigozubeldia/cosmocnc.

Uncovering the Invisible: A Study of Gaia18ajz, a Candidate Black Hole Revealed by Microlensing

Recent IoA Publications - Fri, 15/03/2024 - 10:50
arXiv:2403.09006v1 Announce Type: new Abstract: Identifying black holes is essential for comprehending the development of stars and uncovering novel principles of physics. Gravitational microlensing provides an exceptional opportunity to examine an undetectable population of black holes in the Milky Way. In particular, long-lasting events are likely to be associated with massive lenses, including black holes. We present an analysis of the Gaia18ajz microlensing event, reported by the Gaia Science Alerts system, which has exhibited a long timescale and features indicative of the annual microlensing parallax effect. Our objective is to estimate the parameters of the lens based on the best-fitting model. We utilized photometric data obtained from the Gaia satellite and terrestrial observatories to investigate a variety of microlensing models and calculate the most probable mass and distance to the lens, taking into consideration a Galactic model as a prior. Subsequently, we applied a mass-brightness relation to evaluate the likelihood that the lens is a main sequence star. We also describe DarkLensCode, an open-source routine which computes the distribution of probable lens mass, distance and luminosity employing the Galaxy priors on stellar density and velocity for microlensing events with detected microlensing parallax. We modelled Gaia18ajz event and found its two possible models with most likely Einstein timescale of $t_\mathrm{E}=316^{+36}_{-30}$ days and $t_\mathrm{E}=299^{+25}_{-22}$ days. Applying Galaxy priors for stellar density and motion, we calculated the most probable lens mass of $M_L = 5.6^{+7.5}_{-2.5} M_\odot$ located at $D_S = 1.05^{+0.78}_{-0.60}\,\text{kpc}$ or $M_L = 12.0^{+14.9}_{-5.4} M_\odot$ located at $D_S = 1.18^{+0.82}_{-0.63}\,\text{kpc}$. Our analysis of the blended light suggests that the lens is likely a dark remnant of stellar evolution, rather than a main sequence star.

Thu 02 May 16:00: Experimental Studies of Black Holes: Status & Prospects

Next Colloquia - Thu, 14/03/2024 - 11:19
Experimental Studies of Black Holes: Status & Prospects

Abstract not available

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Categories: Talks

Tue 19 Mar 11:15: Source dynamics and evolution of low-luminosity FRII radio galaxies

Next External Talks - Thu, 14/03/2024 - 10:10
Source dynamics and evolution of low-luminosity FRII radio galaxies

I will present new VLA observations that reveal the structure of a new population of low-luminosity FRII radio galaxies discovered in LoTSS. Fanaroff and Riley (1974) identified a luminosity break between their two morphological classes. FRIs are defined to be low-luminosity, centre bright jets and the higher luminosity FRI Is have jets that are edge brightened and terminate in hotspots. Using LoTSS DR1 , Mingo et al (2019) demonstrated an overlap in luminosity between FRI and FRII morphology rather than a clear divide, discovering a sub-sample of FRI Is with luminosities up to 3 magnitudes lower than the typical FR break. A population of low-luminosity FRI Is raises questions about their origins; are they older, fading FRI Is, or hosted by lower mass galaxies? Our new VLA observations of a sample of LoTSS-selected low-luminosity FRI Is allow us to make comparisons between the two FRII luminosity populations on the prevalence of hotspots, as well as morphological and spectral differences.

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Categories: Talks

Financial Analyst - Research and Grants (Fixed term) (Internal Applicants only)

Vacancies - Thu, 14/03/2024 - 00:00

The Institute of Astronomy (IoA) is seeking a highly organized and proactive individual to join our Department as a Finance Analyst - Research and Grants. As the primary point of contact for research funding matters, you will play a crucial role in providing expert advice and guidance to our staff. Your responsibilities will encompass a wide range of financial activities related to research grants, including collaboration with other departments and the comprehensive management of research grants from application to post-award stages. Full training will be provided.

Key Responsibilities include:

  • Take the lead in coordinating costing and budgeting for complex research grant applications.
  • Provide clear and accurate advice to staff regarding funder requirements and research grant applications and management.
  • Develop effective systems and processes to monitor the funding of research projects.
  • Generate financial management reports and perform data analysis to provide regular updates on the status of research funding.
  • Identify and share relevant funding opportunities with researchers and academics within the Department.

Working to deadlines, high levels of accuracy and attention to detail is key to providing an efficient service in this friendly and welcoming department, who put excellence and wellbeing at the forefront. We are actively looking for candidates who possess prior experience in a financial role. It would be advantageous if you have also worked in a research grant administration capacity, utilising costing tools, financial systems, and spreadsheets. However, we are also keen to receive applications from candidates who are enthusiastic about expanding their skill set and are eager to learn the various facets of research grants administration. We would be fully supportive of considering applications from candidates with this enthusiasm as we will be able to provide role-specific training to support their development.

This position offers a competitive salary at Grade 5 (£29,605- £33,966), commensurate with the applicant's level of expertise and experience. This role is available to internal applicants only.

This role is based in the Institute's beautiful grounds in West Cambridge, and on confirmation of your appointment, the successful candidate will adopt the department's hybrid working model consisting of work at home and on-site alongside other members of the Professional Services Team.

Informal enquiries are welcomed and can be made by email to David Savidge, Deputy Departmental Administrator via email at: dsavidge@ast.cam.ac.uk. Any questions regarding the application process should be directed to the HR team at the Institute of Astronomy at: HR@ast.cam.ac.uk.

Fixed-term: The funds for this post are available until 30th September 2028 in the first instance.

Click the 'Apply' button below to register an account with our recruitment system (if you have not already) and apply online.

Closing Date: Friday, 29th March 2024 at 23:59 GMT

Interview Date: Week commencing 8th April 2024

Please ensure that you outline how you match the criteria for the post and why you are applying for this role on the online application form.

Please include details of your referees, including email address and phone number, one of which must be your most recent line manager.

Please quote reference LG36910 on your application and in any correspondence about this vacancy.

The University actively supports equality, diversity and inclusion and encourages applications from all sections of society.

The University has a responsibility to ensure that all employees are eligible to live and work in the UK.

The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems IV: NIRISS Aperture Masking Interferometry Performance and Lessons Learned

Recent IoA Publications - Wed, 13/03/2024 - 14:04
arXiv:2310.11499v2 Announce Type: replace Abstract: We present a performance analysis for the aperture masking interferometry (AMI) mode on board the James Webb Space Telescope Near Infrared Imager and Slitless Spectrograph (JWST/NIRISS). Thanks to self-calibrating observables, AMI accesses inner working angles down to and even within the classical diffraction limit. The scientific potential of this mode has recently been demonstrated by the Early Release Science (ERS) 1386 program with a deep search for close-in companions in the HIP 65426 exoplanetary system. As part of ERS 1386, we use the same data set to explore the random, static, and calibration errors of NIRISS AMI observables. We compare the observed noise properties and achievable contrast to theoretical predictions. We explore possible sources of calibration errors and show that differences in charge migration between the observations of HIP 65426 and point-spread function calibration stars can account for the achieved contrast curves. Lastly, we use self-calibration tests to demonstrate that with adequate calibration NIRISS F380M AMI can reach contrast levels of $\sim9-10$ mag at $\gtrsim \lambda/D$. These tests lead us to observation planning recommendations and strongly motivate future studies aimed at producing sophisticated calibration strategies taking these systematic effects into account. This will unlock the unprecedented capabilities of JWST/NIRISS AMI, with sensitivity to significantly colder, lower-mass exoplanets than lower-contrast ground-based AMI setups, at orbital separations inaccessible to JWST coronagraphy.

SIDE-real: Truncated marginal neural ratio estimation for Supernova Ia Dust Extinction with real data

Recent IoA Publications - Wed, 13/03/2024 - 14:00
arXiv:2403.07871v1 Announce Type: new Abstract: We present the first fully simulation-based hierarchical analysis of the light curves of a population of low-redshift type Ia supernovae (SNae Ia). Our hardware-accelerated forward model, released in the Python package slicsim, includes stochastic variations of each SN's spectral flux distribution (based on the pre-trained BayeSN model), extinction from dust in the host and in the Milky Way, redshift, and realistic instrumental noise. By utilising truncated marginal neural ratio estimation (TMNRE), a neural network-enabled simulation-based inference technique, we implicitly marginalise over 4000 latent variables (for a set of $\approx 100$ SNae Ia) to efficiently infer SN Ia absolute magnitudes and host-galaxy dust properties at the population level while also constraining the parameters of individual objects. Amortisation of the inference procedure allows us to obtain coverage guarantees for our results through Bayesian validation and frequentist calibration. Furthermore, we show a detailed comparison to full likelihood-based inference, implemented through Hamiltonian Monte Carlo, on simulated data and then apply TMNRE to the light curves of 86 SNae Ia from the Carnegie Supernova Project, deriving marginal posteriors in excellent agreement with previous work. Given its ability to accommodate arbitrarily complex extensions to the forward model -- e.g. different populations based on host properties, redshift evolution, complicated photometric redshift estimates, selection effects, and non-Ia contamination -- without significant modifications to the inference procedure, TMNRE has the potential to become the tool of choice for cosmological parameter inference from future, large SN Ia samples.