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Four New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , , , on November 9, 2024 by telescoper

Once again it’s time for a quick update of activity at the Open Journal of Astrophysics. Since the last update a week ago we have published  four papers, which takes the count in Volume 7 (2024) up to 102 and the total published altogether by OJAp up to 217.   This means not only that we have reached a century for the year but also that so far in 2024 we have published more than double the number of papers that we published in all of 2023. I blogged about the significance of the figure 217 here.

In chronological order, the four papers published this week, with their overlays, are as follows. You can click on the images of the overlays to make them larger should you wish to do so.

First one up is “A generative model for Gaia astrometric orbit catalogs: selection functions for binary stars, giant planets, and compact object companions” by Kareem El-Badry (Caltech, USA), Casey Lam (Carnegie Observatories), Berry Holl & Jean-Louis Halbwachs (U. Geneva), Hans-Walter Rix (MPA Heidelberg, Germany), Tsevi Mazeh (Tel Aviv, Israel) and Sahar Shahaf (Weizmann Institute of Science, Israel). This one is in the folder Solar and Stellar Astrophysics. The paper presents a forward method for estimating the selection function (i.e. the probability of a system with a given set of parameters being included in a catalog). It was published on November 4th 2024.

Here is a screen grab of the overlay, which includes the abstract:

 

You can find the officially accepted version of the paper on the arXiv here.

The second paper to announce, published on 5th November 2024. is “Primordial magnetogenesis in a bouncing model with dark energy” by Marcus V. Bomfim (Rio de Janeiro, Brazil), Emmanuel Frion (Western U. Canada), Nelson Pinto-Neto (Espírito Santo, Brazil), and Sandro D. P. Vitenti (Paraná, Brazil). This paper, in the section on Cosmology and NonGalactic Astrophysics, presents a discussion of the possible generation of magnetic fields on cosmological scales by in a model involving a scalar field coupled to electromagnetism

You can see the overlay here:

 

 

 

The accepted version of this paper can be found on the arXiv here.

The third paper, published on 6th November 2024 in the folder marked Astrophysics of Galaxies, is called  “Evidence for large scale compressible turbulence in the ISM of CSWA13, a star-Forming Lensed Galaxy at z = 1.87 with outflowing wind” by Itzhak Goldman (Tel Aviv, Israel). It presents a statistical analysis of the spatial distribution and kinematics of nebular gas with discussion of the nature of the turbulence present.

Here is the overlay

 

 

The final version accepted on arXiv is here.

Last in this batch is “Star formation in the high-extinction Planck cold clump PGCC G120.69+2.66” by Anlaug Amanda Djupvik (Aarhus, Denmark), João L. Yun (Lisbon, Portugal), and Fernando Comerón (ESO, Garching, Germany). It was published on 7th November 2024 in the folder marked Astrophysics of Galaxies. The paper uses imaging and spectroscopy  information to identify sites of star formation in a molecular cloud. This is the overlay:

You can find the official accepted version on the arXiv here.

That’s all for now. I will post another update in a week.

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Another Edgeworth Connection

Posted in History, The Universe and Stuff with tags , , , , , , , , , on November 3, 2024 by telescoper

A week or so ago I posted an item about the Edgeworth family that included a reference to Kenneth Edgeworth, an amateur astronomer of some note who first posited the existence of what is now known as the Kuiper belt. Here’s another interesting connection. Kenneth Edgeworth was born in 1880 in Daramona House in Street in County Westmeath. The owner of this house was Edgeworth’s uncle, another astronomer called William Edward Wilson who built an observatory next to Daramona House.

Here are pictures of (left) house and (right) the observatory, neither of look in particularly good condition!

After independence, many of the large houses owned by the rich Anglo-Irish families who had run Ireland until then fell into disrepair or were destroyed.

Anyway, on top of the two-storey observatory building there used to be a dome that housed a 24″ Grubb reflecting telescope. Here’s an old picture showing what it looked like in better times, around 1900:

The dome is no longer there, and neither is the telescope. The latter was donated to the University of London in 1925 eventually housed in the Observatory at Mill Hill, now run by University College London. Here is an excerpt from the history of the University of London Observatory:

W.E. Wilson established an observatory at Daramona, Street, County Westmeath, in 1871 and equipped it with a 12-inch equatorial reflector by Grubb. Wilson (born in 1851, elected FRS in 1896, an original member of the BAA, awarded an honorary DSc by the University of Dublin in 1901, High Sheriff of Co. Westmeath in 1894), observed the transit of Venus in 1882 and solar eclipses at Oran in 1870 and Spain in 1900, published many papers in Proc. R. Soc, Proc. R. Dublin Soc., Proc. R. Irish Acad., etc., and died in 1908) enlarged his observatory in 1881 and installed a 24-inch reflector by Grubb on the mounting previously used for the 12-inch reflector. Ten years later a new mounting was constructed. It is this mounting which was moved to Mill Hill in 1928. Dr. Wilson used his telescope to make some of the best photographs of his time of star clusters and nebulae, and he worked extensively on problems of solar physics and the solar constant. The telescope may be used in Newtonian and Cassegrain forms; the focal length of the mirror is 10 feet and the equivalent focal length at the Cassegrain focus is approximately 42 feet. The telescope was moved in 1928 from Ireland to University College, where minor modifications were made to the focussing arrangements and plate-holder, and an electric motor was added to rewind the driving clock automatically.

The Wilson telescope was retired from active service in 1974 and moved to the World Museum in Liverpool where, as far as I know, it remains on display to this day.

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Three New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , on November 2, 2024 by telescoper

It’s Saturday, so it’s time once again for another summary of business at the  Open Journal of Astrophysics. This week I have three papers to announce, which brings the total we have published so far this year (Vol. 7) to 98 and the total published by OJAp to 213.

First one up, published on Tuesday 29th October 2024, is “Cosmology with shear ratios: a joint study of weak lensing and spectroscopic redshift datasets” by Ni Emas & Chris Blake (Swinburne U., Australia), Rossana Ruggeri (Queensland U, Australia) and Anna Porredon (Ruhr University, Bochum, Germany). This paper is in the folder marked Cosmology and NonGalactic Astrophysics. The paper investigates the use of shear ratios as a cosmological diagnostic, with applications to lensing surveys

Here is a screen grab of the overlay, which includes the abstract:

You can read the paper directly on arXiv here.

The second paper to present, also published on Tuesday 29th October 2024, is “Echo Location: Distances to Galactic Supernovae From ASAS-SN Light Echoes and 3D Dust Maps” by Kyle D. Neumann (Penn State), Michael A. Tucker & Christopher S. Kochanek (Ohio State), Benjamin J. Shappee (U. Hawaii), and K. Z. Stanek (Ohio State), all based in the USA. This paper is in the folder marked High-Energy Astrophysical Phenomena and it presents a new approach to estimating the distance to a source by combining light echoes with recent three-dimensional dust maps with application to supernova distances.

The overlay looks like this:

 

 

You can read this paper directly on the arXiv here.

Last, but by no means least, comes  “A deconstruction of methods to derive one-point lensing statistics” by Viviane Alfradique (Universidade Federal do Rio De Janeiro, Brazil), Tiago Castro (INAF Trieste, Italy), Valerio Marra (Trieste), Miguel Quartin (Rio de Janeiro), Carlo Giocoli (INAF Bologna, Italy), and Pierluigi Monaco (Trieste).  Published in the folder marked Cosmology and NonGalactic Astrophysics, it describes a comparative study of different methods of approximating the one-point probability density function (PDF) for use in the statistical analysis of gravitational lensing.

Here is a screengrab of the overlay:

 

To read the accepted version of this on the arXiv please go here.

That’s it for this week. I hope to post another update next weekend, by when we might well have reached a century for this year!

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New Image Casts Doubt on Standard Cosmological Theory

Posted in The Universe and Stuff with tags , , on October 28, 2024 by telescoper

Scarcely a day goes by without some news outlet or other claiming that recent observations have ruled out the standard cosmological model. This remarkable new image does however seem to cast doubt on many aspects of the Big Bang Theory:

For one thing, it seems to be much less homogeneous and isotropic than we previously imagined. Although the composition is uncertain, it also seems to have a much higher fraction of baryonic matter than currently assumed. Whether or not this picture overthrows the standard model or not, it seems likely to lead to a revival of interest in cosmological applications of the Burgers equation.

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Two New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , on October 26, 2024 by telescoper

It’s Saturday morning again so here’s another report on activity at the  Open Journal of Astrophysics.  Since the last update we have published two more papers, taking  the count in Volume 7 (2024) up to 95 and the total published by OJAp up to 210.  We’ve still got a few in the pipeline waiting for the final versions to appear on arXiv so I expect we’ll reach the 100 mark for 2024 in the next couple of weeks.

The first paper of the most recent pair, published on October 22 2024,  and in the folder marked Astrophysics of Galaxies, is “Cloud Collision Signatures in the Central Molecular Zone”  by Rees A. Barnes and Felix D. Priestley (Cardiff University, UK) .  This paper presents an analysis of combined hydrodynamical, chemical and radiative transfer simulations of cloud collisions in the Galactic disk and Central Molecular Zone (CMZ).

Here is a screen grab of the overlay which includes the abstract:

 

 

You can click on the image of the overlay to make it larger should you wish to do so.  You can find the officially accepted version of this paper on the arXiv here.

The second paper has the title “Partition function approach to non-Gaussian likelihoods: macrocanonical partitions and replicating Markov-chains” and was published October 25th 2024. The authors are Maximilian Philipp Herzog, Heinrich von Campe, Rebecca Maria Kuntz, Lennart Röver and Björn Malte Schäfe (all of Heidelberg University, Germany). This paper, which is in  the folder marked Cosmology and NonGalactic Astrophysics, describes a method of macrocanonical sampling for Bayesian statistical inference, based on the macrocanonical partition function, with applications to cosmology.

Here is a screen grab of the overlay which includes the abstract:

 

You can click on the image of the overlay to make it larger should you wish to do so. You can find the officially accepted version of the paper on the arXiv here.

That concludes this week’s update. More  next week!

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Edgeworth Connections

Posted in History, The Universe and Stuff with tags , , , , , on October 25, 2024 by telescoper

It’s a small world.

This year I am supervising an undergraduate project student who is looking at approximations to probability distribution functions. This project was inspired by a nice paper on the arXiv by Elena Sellentin, Andrew Jaffe and Alan Heavens about the use of the Edgeworth series which I blogged about here.

It turns out that the student who picked this project hails from a place very close to Edgeworthstown in County Longford. I’ve been through there on the train going to and from Sligo, but I never thought much about the possible connection, assuming the name was a coincidence. When I met my project student yesterday for our weekly discussion, however, he told me he had looked into it and the results are very interesting.

The Edgeworth series was invented by Francis Ysidro Edgeworth (1845-1926) who was a political economist and philosopher was born in Edgeworthstown. He was the grandson of the Richard Lovell Edgeworth (1744-1817) who had no fewer than 22 children (including the novelist Maria Edgeworth) and was a founder member of the Royal Irish Academy. In a manner not untypical of the Anglo-Irish landed gentry, the Edgeworths renamed the local town from Meathas Troim (anglicized form Mostrim), c.f. Parsonstown.

There is a directly astronomical connection with the Edgeworth family too. Kenneth Edgeworth (1880-1972) was another member of the Edgeworth dynasty, `one of ‘the archetypal gentleman literary and scientific families’ who had sufficient private income to be able to pursue a diverse range of interests. Kenneth Edgeworth was an independent theoretical astronomer, best known for proposing the existence of a disc of bodies beyond the orbit of Neptune in the 1930s. Observations later confirmed the existence of this structure, often called the Kuiper belt or, especially in Irish circles, the Edgeworth-Kuiper belt.

Here’s the front page of one of his astronomical publications:

Anyway, what’s the probability that a student would randomly pick a project involving a method invented a person born just a few miles away from his family home?

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Pastamarkers: astronomy meets gastronomy

Posted in The Universe and Stuff with tags , , , , on October 24, 2024 by telescoper

It’s time to share a paper on arXiv at the interface between astronomy and gastronomy. Here is the abstract:

We aim at facilitating the visualization of astrophysical data for several tasks, such as uncovering patterns, presenting results to the community, and facilitating the understanding of complex physical relationships to the public. We present pastamarkers, a customized Python package fully compatible with matplotlib, that contains unique pasta-shaped markers meant to enhance the visualization of astrophysical data. We prove that using different pasta types as markers can improve the clarity of astrophysical plots by reproducing some of the most famous plots in the literature.

arXiv:2403.20314

Here’s an example of a colour-magnitude diagram plotted with pasta markers, with the main sequence as Lasagne, etc.

You can download the pastamarkers package here.

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“Optimized” Beer Glass Shapes

Posted in The Universe and Stuff with tags , , , on October 21, 2024 by telescoper

I couldn’t resist sharing a piece of fundamental research I found in an article on the arXiv withthe abstract:

This paper addresses the problem of determining the optimum shape for a beer glass that minimizes the heat transfer while the liquid is consumed, thereby keeping it cold for as long as possible. The proposed solution avoids the use of insulating materials. The glass is modeled as a body of revolution generated by a smooth curve, constructed from a material with negligible thermal resistance, but insulated at the base. The ordinary differential equation describing the problem is derived from the first law of Thermodynamics applied to a control volume encompassing the liquid. This is an inverse optimization problem, aiming to find the shape of the glass (represented by curve S) that minimizes the heat transfer rate. In contrast, the direct problem aims to determine the heat transfer rate for a given geometry. The solution obtained here is analytic, and the resulting function describing the relation between height ans radius of the glass, is in closed form, providing a family of optimal glass shapes that can be manufactured by conventional methods. Special attention is payed to the dimensions and the capacity of the resulting shapes.

arXiv:2410.12043v1

The author’s favourite shape is this:

Of course those of us who are used to proper beer don’t really want it to be cold in the first place, but I hope this doesn’t sound bitter. My main reservation about the conclusion of the paper is that it doesn’t seem to take into account how easy it is to drink from the glass. In that respect, I’m not convinced by the shape above!

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Six New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , , , , , on October 19, 2024 by telescoper

It’s Saturday morning again and time to post an update of activity at the Open Journal of Astrophysics. As last week there are six papers to announce, bringing the count in Volume 7 (2024) up to 93 and the total altogether up to 208.

In chronological order, the six papers published this week, with their overlays, are as follows. You can click on the images of the overlays to make them larger should you wish to do so.

First one up, published on Monday 14th October 2024, is in the folder marked Cosmology and NonGalactic Astrophysics and is called “Backreaction in Numerical Relativity: Averaging on Newtonian gauge-like hypersurfaces in Einstein Toolkit cosmological simulations“. This paper presents a numerical study of the effect of local inhomogeneities on the dynamical evolution of the Universe, i.e. the so-called “backreaction” problem; the authors are Alexander Oestreicher and Sofie Marie Koksbang of the University of Southern Denmark, Odense, Denmark.

Here is a screen grab of the overlay, which includes the abstract:

You can find the officially accepted version of the paper on the arXiv here.

The second paper to announce, published on 15th October 2024, is “Weak-Lensing Shear-Selected Galaxy Clusters from the Hyper Suprime-Cam Subaru Strategic Program: II. Cosmological Constraints from the Cluster Abundance” by I-Non Chiu (National Cheng Kung University, Taiwan) and 11 others based in Taiwan, Japan, India and the USA. This paper, which is also in the folder Cosmology and NonGalactic Astrophysics  presents constraints on cosmological parameters obtained from a sample of galaxy clusters

You can see the overlay here:

The accepted version of this paper can be found on the arXiv here.

The third paper is “Image formation near hyperbolic umbilic in strong gravitational lensing” by Ashish Kumar Meena (Ben Gurion University, Israel) and Jasjeet Singh Bagla (IISER Mohali, India). It presents a detailed theoretical discussion of a particular form of strong gravitational lensing and its observational consequences; it is in the folder Astrophysics of Galaxies and was published on October 15th 2024.

The overlay is here:

 

The officially accepted version can be found on arXiv here.

The fourth paper, published on 16th October 2024 and in the folder Astrophysics of Galaxies,  is “Weak Gravitational Lensing around Low Surface Brightness Galaxies in the DES Year 3 Data” by N. Chicoine (University of Chicago, USA) et al. (105 authors; DES Collaboration). It presents a  demonstration of the viability of using weak gravitational lensing to constrain the halo masses of low surface brightness galaxies.

The overlay is here

 

You can find the officially accepted version of this paper here.

The fifth paper in this batch is “Imprints of interaction processes in the globular cluster system of NGC 3640” by Ana I Ennis (Waterloo, Canada) and Juan Pablo Caso & Lilia Patricia Bassino (Instituto de Astrofísica de La Plata, Argentina). This one was also published on 16th October 2024 and is in the folder Astrophysics of Galaxies, Here is the overlay

 

 

You can find the official accepted version on the arXiv here.

Finally for this week we have “On the nature of the C IV-bearing circumgalactic medium at 𝒛∼𝟏” by Suyash Kumar, Hsiao-Wen Chen, Zhijie Qu & Mandy C. Chen (U. Chicago), Fakhri S. Zahedy (U. North Texas), Sean D. Johnson (Carnegie Observatories), Sowgat Muzahid (IUCAA, India) and Sebastiano Cantalupo (U. Milan Bicocca)

The overlay is here

 

You can find the officially-accepted version on arXiv here.

That’s it for now. More next week!

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A Taste of the Euclid Survey

Posted in Euclid, The Universe and Stuff with tags , , , on October 15, 2024 by telescoper

Today (15th October 2024) saw the release of a sneak preview of the main survey of the European Space Agency’s Euclid survey at the International Astronautical Congress in Milan. Here’s the key image.

This image is not at full science resolution of the Euclid survey and is meant primarily as an appetizer. The resolution is11Kx4K,  and is processed by the same pipeline that produced the Euclid Early Release Observations featured here and here. You can find more detail about these images here and here. I have taken this from the latter article:

Euclid has been surveying the sky since 14 February 2024 and data processing is in full swing – the first public release of 53 deg² of science-grade Wide Survey data will take place in March next year. But how much data has Euclid already observed and how can we possibly visualize this? At a rate of 10 deg² per day, the Euclid Wide Survey has already surpassed 1000 deg², that is 5000x the apparent size of the Moon in the sky! Now ESA has put out a first set of images that allow to grasp how much data Euclid is and will be producing.

There’s also this explanatory video:

This is just taster. The main survey will take many years to complete. But it’s a start…

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