Archive for intrinsic alignments

Weekly Update from the Open Journal of Astrophysics – 06/12/2025

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , , , , , , , , , , , , , , on December 6, 2025 by telescoper

Once again it’s time for the usual Saturday morning update of the week’s new papers at the Open Journal of Astrophysics. Since the last update we have published a further six papers, which brings the number in Volume 8 (2025) up to 190, and the total so far published by OJAp up to 425. I blogged about the significance of the latter figure here.

The first paper this week is “The galaxy-IGM connection in THESAN: observability and information content of the galaxy-Lyman-alpha cross-correlation at z>6” by Enrico Garaldi (U. Tokyo, Japan), Verena Bellscheidt (Tech. U. Munich, Germany), Aaron Smith (U. Texas Austin, USA) and Rahul Kannan (York U. Canada). This paper was published on Monday 1st December 2025 in the folder Cosmology and Nongalactic Astrophysics. It describes an investigation of the impact of observational limitations on the ability to retrieve the intrinsic galaxy-Lyman-alpha cross correlation from line-of-sight observations.

The overlay is here:

 

 

You can find the officially accepted version on arXiv here and the Fediverse announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "The galaxy-IGM connection in THESAN: observability and information content of the galaxy-Lyman-alpha cross-correlation at z>6" by Enrico Garaldi (U. Tokyo, Japan), Verena Bellscheidt (Tech. U. Munich, Germany), Aaron Smith (U. Texas Austin, USA) and Rahul Kannan (York U. Canada)

doi.org/10.33232/001c.151666

December 1, 2025, 8:37 am 1 boosts 0 favorites

The second paper of the week is “A Less Terrifying Universe? Mundanity as an Explanation for the Fermi Paradox” by Robin H.D. Corbet (U. Maryland, USA). This paper was published on 1st December 2025 in the folder Instrumentation and Methods for Astrophysics. It presents a discussion of possible explanations for the lack of s evidence for the presence of technology-using extraterrestrial civilizations in the Galaxy (usually called the Fermi paradox). The overlay is here:

 

 

You can find the official version of this one on arXiv here. The federated announcement on Mastodon is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "A Less Terrifying Universe? Mundanity as an Explanation for the Fermi Paradox" by Robin H.D. Corbet (U. Maryland, USA)

doi.org/10.33232/001c.151454

December 1, 2025, 8:50 am 2 boosts 2 favorites

 

Next one up is “Sulphur abundances in star-forming regions from optical emission lines: A new approach based on photoionization models consistent with the direct method” by Enrique Pérez-Montero, Borja Pérez-Díaz, & José M. Vílchez ( (Instituto de Astrofísica de Andalucía, Spain), Igor A. Zinchenko (LMU, Germany), Asier Castrillo, Marta Gavilán, Sandra Zamora & Ángeles I. Díaz (Universidad Autonoma de Madrid, Spain). This was published on 1st December 2025 in the folder Astrophysics of Galaxies. This study uses the emission lines produced in the optical part of the spectrum and with photoionization models to derive sulphur chemical abundances in the gas-phase of star-forming galaxies.

The overlay is here:

 

 

You can find the official accepted version on arXiv here. The fediverse announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Sulphur abundances in star-forming regions from optical emission lines: A new approach based on photoionization models consistent with the direct method" by Enrique Pérez-Montero, Borja Pérez-Díaz, & José M. Vílchez ( (Instituto de Astrofísica de Andalucía, Spain), Igor A. Zinchenko (LMU, Germany), Asier Castrillo, Marta Gavilán, Sandra Zamora & Ángeles I. Díaz (Universidad Autonoma de Madrid , Spain)

doi.org/10.33232/001c.151253

December 1, 2025, 9:12 am 0 boosts 0 favorites

The fourth article of the week is “Bayesian Posteriors with Stellar Population Synthesis on GPUs” by Georgios Zacharegkas & Andrew Hearin (Argonne National Laboratory, USA) and Andrew Benson (Carnegie Observatories, USA). This is an exploration of a range of computational techniques aimed at accelerating Stellar Population Synthesis predictions of galaxy photometry using the JAX library to target GPUs (Graphics Processing Units, in case you didn’t know). This paper was published on Tuesday December 2nd 2025 in the folder Astrophysics of Galaxies.

The overlay is here:

 

You can find the official published version on arXiv here. The Fediverse announcement follows:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Bayesian Posteriors with Stellar Population Synthesis on GPUs" by Georgios Zacharegkas & Andrew Hearin (Argonne National Laboratory, USA) and Andrew Benson (Carnegie Observatories, USA)

doi.org/10.33232/001c.151255

December 2, 2025, 7:38 am 3 boosts 1 favorites

Next one up is “IAEmu: Learning Galaxy Intrinsic Alignment Correlations” by Sneh Pandya Yuanyuan Yang, Nicholas Van Alfen, Jonathan Blazek and Robin Walters (Northeastern University, Boston, USA). This presents a neural-network-based emulator that predicts the galaxy position-position, position-orientation, and orientation-orientation, correlation functions and their uncertainties using mock catalogs based on the halo occupation distribution (HOD) framework. It was published on December 2nd 2025 in the folder Cosmology and Nongalactic Astrophysics. The overlay is here:

The official accepted version can be found on arXiv here. The Mastodon announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "IAEmu: Learning Galaxy Intrinsic Alignment Correlations" by Sneh Pandya Yuanyuan Yang, Nicholas Van Alfen, Jonathan Blazek and Robin Walters (Northeastern University, Boston, USA)

doi.org/10.33232/001c.151749

December 2, 2025, 7:52 am 1 boosts 0 favorites

The last paper for this weel is “Unraveling the Nature of the Nuclear Transient AT2020adpi” by Paarmita Pandey (Ohio State University, USA) and a team of 15 others based in the USA, UK and Australia. This was published on Thursday December 4th 2025 in the folder High-Energy Astrophysical Phenomena. It is an investigation into a particular transient event AT2020adpi and a discussion of whether it is an extreme example of AGN variability or a Tidal Disruption Event (TDE). The overlay is here:

You can find the officially-accepted version on arXiv here, and the Mastodon announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Unraveling the Nature of the Nuclear Transient AT2020adpi" by Paarmita Pandey (Ohio State University, USA) and 15 others based in the USA, UK and Australia

doi.org/10.33232/001c.151453

December 4, 2025, 8:48 am 1 boosts 0 favorites

And that concludes the update for this week. I will do another next Saturday.

Weekly Update from the Open Journal of Astrophysics – 27/09/2025

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , , , , , , , , , on September 27, 2025 by telescoper

It’s Saturday again, so it’s time for a summary of the week’s new papers at the Open Journal of Astrophysics. Since the last update we have published five new papers, which brings the number in Volume 8 (2025) up to 141, and the total so far published by OJAp up to 376.

The first paper to report this week is “The Bispectrum of Intrinsic Alignments: Theory Modelling and Forecasts for Stage IV Galaxy Surveys” by Thomas Bakx (Utrecht U., NL), Alexander Eggemeier (U. Bonn, DE), Toshiki Kurita (MPA Garching, DE), Nora Elisa Chisari (Leiden U., NL) and Zvonimir Vlah (Ruđer Bošković Institute, Croatia). This paper was published on Monday 22nd September 2025 in the folder Cosmology and NonGalactic Astrophysics. It studies the bispectrum of intrinsic galaxy alignments, a possible source of systematic errors in extracting cosmological information from the analysis of weak lensing surveys.

The overlay is here:

You can make this larger by clicking on it.  The officially accepted version of this paper can be found on the arXiv here.

The second paper this week, published on Tuesday 23rd September 2025 is “Reanalysis of Stage-III cosmic shear surveys: A comprehensive study of shear diagnostic tests” by Jazmine Jefferson (University of Chicago, USA) and 13 others for the LSST Dark Energy Science Collaboration. It is also in the folder Cosmology and NonGalactic Astrophysics; it describes diagnostic tests on three public shear catalogs (KiDS-1000, Year 3 DES-Y3 s, and Year 3 HSC-Y3); not all the surveys pass all the tests.

The corresponding overlay is here:

You can find the officially accepted version on arXiv here.

The third one this week, published on Wednesday 24th September 2025 in the folder Astrophysics of Galaxies, is “Is feedback-free star formation possible?” by Andrea Ferrara, Daniele Manzoni, and Evangelia Ntormousi (all of the Scuola Normale Superiore, Pisa, Italy). This paper presents an argument that Lyman-alpha radiation pressure strongly limits star formation efficiency, even at solar metallicities, so that a feedback-free star formation phase is not possible without feedback. The overlay is here:

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

Next we have “Microphysical Regulation of Non-Ideal MHD in Weakly-Ionized Systems: Does the Hall Effect Matter?” by Philip F. Hopkins (Caltech, USA), Jonathan Squire (U. Otago, New Zeland), Raphael Skalidis (Caltech) and Nadine H. Soliman (Caltech). This was also published on Wednesday 24th September 2025, but in the folder Earth and Planetary Astrophysics. It presents an improved treatment of non-ideal effects in magnetohydrodynamics, particularly the Hall effect, and a discussion of the implications for weakly-ionized astrophysical systems.

The corresponding overlay is here:

 

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

The fifth, and last, one for this week is “The Local Volume Database: a library of the observed properties of nearby dwarf galaxies and star clusters” by Andrew B. Pace (University of Virginia, USA). This one was published on Friday 26th September (i.e. yesterday) in the folder Astrophysics of Galaxies. It presents a catalogue of positional, structural, kinematic, chemical, and dynamical parameters for dwarf galaxies and star clusters in the Local Volume. The overlay is here:

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

 

And that concludes the report for this week. I’ll post another update next Saturday.

Three New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , , , , on June 8, 2024 by telescoper

Time for another roundup of business at the  Open Journal of Astrophysics. This time I have three papers to announce, which brings the total we have published so far this year (Vol. 7) to 45 and the total published by OJAp to 160. We’re still on track to publish around 100 papers this year or more, compared to last year’s 50.

First one up, published on 3rd June 2024, is “Log-Normal Waiting Time Widths Characterize Dynamics” by Jonathan Katz of Washington University (St Louis, Missouri, USA). This paper presents a discussion of the connection between waiting time distributions and dynamics for aperiodic astrophysical systems, with emphasis on log-normal distributions.  This paper is in the folder marked High-Energy Astrophysical Phenomena.

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 is “An Empirical Model For Intrinsic Alignments: Insights From Cosmological Simulations” by Nicholas Van Alfen (Northeastern University, Boston, USA), Duncan Campbell (Carnegie Mellon University, Pittsburgh, USA), Jonathan Blazek (Northeastern University), C. Danielle Leonard (Newcastle University, UK), Francois Lanusse (Université Paris-Saclay, France), Andrew Hearin (Argonne National Laboratory, USA), Rachel Mandelbaum (Carnegie Mellon University) and The LSST Dark Energy Science Collaboration.  This paper presents an extension of the halo model (specifically the Halo Occupation Distribution, HOD) to include intrinsic alignment effects for the study of weak gravitational lensing. This paper is in the folder marked Cosmology and Nongalactic Astrophysics. It was published on Tuesday June 4th 2024.

The overlay looks like this:

 

 

You can read this paper directly on the arXiv here.

Last, but by no means least, comes  “Towards Cosmography of the Local Universe”  which proposes the multipoles of the distance-redshift relation as new cosmological observables that have a direct physical interpretation in terms of kinematical quantities of the underlying matter flow. This was also published on 4th June. The authors are Julian Adamek (IfA Zurich, Switzerland), Chris Clarkson (Queen Mary, London, UK), Ruth Durrer (Geneva, Switzerland), Asta Heinesen (U. Lyon, France & NBI Copenhagen, Denmark), Martin Kunz (Geneva), and Hayley J. Macpherson (Chicago, USA).

Here is a screengrab of the overlay:

 

 

To read the accepted version of this on the arXiv please go here. This paper is also in the folder marked Cosmology and Nongalactic Astrophysics.
That’s it for this week. I aim to post another update next weekend.

 

 

Four New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , on May 11, 2024 by telescoper

It is time yet again for an update of recent activity at the Open Journal of Astrophysics.
This week we have published four papers, which I now present to you. These four take the count in Volume 7 (2024) up to 36 and the total published by OJAp up to 151. I speculated last week that we would probably pass the 150 mark this week, and so we did. We’re still on target to publish around 100 papers this year.
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 “Ephemeris Matching Reveals False Positive Validated and Candidate Planets from the K2 Mission” by Drake A. Lehmann (U. Wisconsin-Madison, USA) and Andrew Vanderburg (MIT, USA). It presents a description and application of a technique for identifying false positives among candidate exoplanets. The paper was published on 7th May 2024, is in the folder marked Earth and Planetary Astrophysics, and can be found here.
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 is “Accuracy requirements on intrinsic alignments for Stage-IV cosmic shear” which is by by Anya Paopiamsap, Natalia Porqueres & David Alonso (Oxford, UK) and Joachim Harnois-Deraps & C. Danielle Leonard (Newcastle, UK). This paper sets about quantifying the permissible level of disagreement between the true intrinsic galaxy alignments and the theoretical models thereof that can be allowed for future Stage-IV cosmic shear surveys. This one is in the folder marked Cosmology and Nongalactic Astrophysics. The paper was published on May 9th 2024 and you can see the overlay here:

The accepted version of this paper can be found on the arXiv here.
The next paper, is in the folder Instrumentation and Methods for Astrophysics and is entitled “Optimal Summary Statistics for X-ray Polarization”. The authors are Jeremy Heyl (Uni. British Columbia, Canada), Denis González-Caniulef (Uni. Toulouse, France) and Ilaria Caiazzo (Caltech, USA). This presents new statistical estimators for use in studies of X-ray polarization, with an analytic discussion of their efficiency. It can be found here and the accepted version can be read on arXiv here. Here is the overlay:

The last paper of this batch is called “B-modes from galaxy cluster alignments in future surveys” and is by Christos Georgiou, Thomas Bakx, Juliard van Donkersgoed and Nora Elisa Chisari, all from Utrecht University in The Netherlands. It presents a discussion of the possible detection of cosmic shear B-modes produced by intrinsic alignments in future galaxy surveys.
Here is the overlay:

You can find the full text for this one on the arXiv here. The primary classification for this one is Cosmology and Nongalactic Astrophysics.
And that ends this week’s update. More next week!

Cosmology Talks: Intrinsic Alignments – A Guide for All Cosmologists

Posted in OJAp Papers, The Universe and Stuff, YouTube with tags , , , , , , , , , on February 24, 2024 by telescoper

I was just thinking this afternoon that I haven’t posted recently any of the Cosmology Talks curated by Shaun Hotchkiss, then I looked and found that I had the perfect excuse for doing so. This particular talk is actually about one of the two new OJAp papers I announced in my previous post, i.e. “The IA Guide: A Breakdown of Intrinsic Alignment Formalisms” and the authors are: Claire Lamman (Harvard, USA);  Eleni Tsaprazi (Stockholm, Sweden);  Jingjing Shi (Tokyo, Japan); Nikolina Niko Šarčević (Newcastle, UK); Susan Pyne (UCL, UK); Elisa Legnani (Barcelona, Spain); and Tassia Ferreira (Oxford, UK).

Here is Shaun’s description of the video:

Claire Lamman, Jingjing Shi, Niko Šarčević, Susan Pyne, Elisa Legnani and Tassia Ferreira tell us about the intrinsic alignments guide they wrote (along with Eleni Tsaprazi, who couldn’t make the video recording).

They wanted to write something that wasn’t quite a review, but also wasn’t quite a set of lecture notes. Instead they aimed for what might be best framed as a “cheat sheet” for intrinsic alignments. Everything you need to know about the topic, compressed into one article. However, there’s still a lot about the topic, so the compression is still 33 pages and 10 figures big.

To construct the guide they broke the topic of intrinsic alignments into sub-fields and then asked questions like “what are the key equations for this sub-field?”, “what are the different notations people use?”, “what might be confusing to a newcomer?” They then wrote the guide to answer those questions, even including subsections with quick definitions of each common term, and short lists of common alternative notations.

And here is the video!

Two New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , on February 24, 2024 by telescoper

It’s Saturday morning in Sydney, and time to post another update relating to the  Open Journal of Astrophysics.  Since the last update we have published two more papers, taking  the count in Volume 7 (2024) up to 15 and the total published by OJAp up to 130. I should have posted these before leaving but it slipped my mind.

The first paper of the most recent pair – published on  Thursday 22nd February – is “Modelling cross-correlations of ultra-high-energy cosmic rays and galaxies” by Federico Urban (Prague, Czech Republic), Stefano Camera (Torino, Italy) and David Alonso (Oxford, UK). It presents a discussion of the possible statistical correlations between Ultra-High-Energy Cosmic-Ray (UHECR) directions in various models and structure in the galaxy distribution and whether or not this signal could be measurable.  This one is in the folder marked “High-Energy Astrophysical Phenomena“.

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.

The second paper was published on Friday 23rd February and has the title “The IA Guide: A Breakdown of Intrinsic Alignment Formalisms” and the authors are: Claire Lamman (Harvard, USA);  Eleni Tsaprazi (Stockholm, Sweden);  Jingjing Shi (Tokyo, Japan); Nikolina Niko Šarčević (Newcastle, UK); Susan Pyne (UCL, UK); Elisa Legnani (Barcelona, Spain); and Tassia Ferreira (Oxford, UK). This one, which is in the folder marked Cosmology and NonGalactic Astrophysics, presents a review of Intrinsic Alignments, i.e. physical correlations involving galaxy shapes, galaxy spins, and larger scale structure, especially important for weak gravitational lensing

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!