Archive for Cosmology

New Publication at the Open Journal of Astrophysics

Posted in Open Access, The Universe and Stuff with tags , , , , , on October 20, 2021 by telescoper

Time to announce another publication in the Open Journal of Astrophysics. This one is the 13th paper in Volume 4 (2021) and the 44th in all.

The latest publication is entitled  The LSST-DESC 3x2pt Tomography Optimization Challengeand is in the folder marked Instrumentation and Methods for Astrophysics, and is especially relevant for cosmology. The paper is led by Joe Zuntz of the University of Edinburgh, and there are 27 authors altogether, scattered across the globe, representing the LSST Dark Energy Science Collaboration.

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

You can find the paper on the Open Journal of Astrophysics site here and can also read it directly on the arXiv here.

Cosmology Talks: James Alvey on Big Bang Nucleosynthesis in 2021

Posted in The Universe and Stuff with tags , , , , , on October 15, 2021 by telescoper

It’s been a while since I last shared another one of those interesting cosmology talks on the Youtube channel curated by Shaun Hotchkiss. This channel features technical talks rather than popular expositions so it won’t be everyone’s cup of tea but for those seriously interested in cosmology at a research level they should prove interesting. I found this one particular interesting as it is a field that I lost track of quite a long time ago and it was great to see what has been going on!

Here James Alvey gives a pedagofical overview of the general state of the field of Big Bang Nucleosynthesis (BBN) in 2021, including the basic physics that goes into BBN calculations through each of the relevant epochs (neutrino decoupling, the deuterium bottleneck, etc). He gives particular emphasis to the recent LUNA measurements of the D + p →γ + 3He reaction (or deuterium + proton goes to photon and 3-Helium). This was previously the source of greatest uncertainty in predicting the final deuterium abundance of BBN. He ends by talking about the implications of the LUNA measurements on possible new physics beyond the standard model, in particular possible thermal relics.

There is a Nature paper about the LUNA results here and  two other papers on this topic by James can be found here and here.

New Publication at the Open Journal of Astrophysics

Posted in Open Access, The Universe and Stuff with tags , , , , , , on September 28, 2021 by telescoper

Time to announce another publication in the Open Journal of Astrophysics. This one is the eleventh paper in Volume 4 (2021) and the 42nd in all.

The latest publication is entitled Squeezing the Axion – it’s about inflationary scalar field perturbations using the squeezed state formalism – and is by

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

You can click on the image to make it larger should you wish to do so. You can find the arXiv version of the paper here. This one is also in the folder marked Cosmology and Non-Galactic Astrophysics.  

P.S. I hope to publish another paper tomorrow…

Astrophysics & Cosmology Masterclass at Maynooth!

Posted in Biographical, Education, Maynooth, The Universe and Stuff with tags , , on September 28, 2021 by telescoper

Regular readers of the blog – both of them – may remember that, after a couple of postponements due to Covid-19,  we presented a Masterclass in Astrophysics & Cosmology in Maynooth on March 25th 2021. Well, owing to popular demand we’ve decided to do a re-run of the event on Friday 12th November 2021 ahead of next year’s CAO cycle.

This will be a half-day virtual event via Zoom. It’s meant for school students in their 5th or 6th year of the Irish system. There might be a few of them or their teachers who see this blog so I thought I’d share the news here. You can find more information, including instructions on how to book a place, here.

Here is the updated official poster and the programme:

I’ll be talking about cosmology early on, while John Regan will talk about black holes. After the coffee break one of our PhD students will talk about why they wanted to study astrophysics. Then I’ll say something about our degree programmes for those students who might be interested in studying astrophysics and/or cosmology as part of a science course. We’ll finish with questions either about the science or the study!

(And at 12 noon I don’t turn into a pumpkin but do have to run off to give a lecture on vector calculus..)

New Publication at the Open Journal of Astrophysics

Posted in Open Access, The Universe and Stuff with tags , , , , , , on September 23, 2021 by telescoper

Time to announce another publication in the Open Journal of Astrophysics. This one is the tenth paper in Volume 4 (2021) and the 41st in all. We actually published this one a couple of days ago but I’ve been so busy with start-of-term shenanigans that I didn’t get time to announce it until this morning.

The latest publication is entitled Consequences of constant elevation scans for instrumental systematics in Cosmic Microwave Background Experiments. The authors are Daniel B. Thomas & Nialh McCallum of Queen Mary, University of London, and Michael Brown of the University of Manchester.

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

You can click on the image to make it larger should you wish to do so. You can find the arXiv version of the paper here. This one is also in the folder marked Instrumentation and Methods for Astrophysics, though it is obviously of relevance to Cosmology and Non-Galactic Astrophysics too.

R.I.P. Thanu Padmanabhan (1957-2021)

Posted in The Universe and Stuff with tags , on September 17, 2021 by telescoper
Prof. Thanu Padmanabhan

It’s my sad task to pass on yet another piece of bad news. Renowned Indian physicist and cosmologist Professor Thanu Padmanabhan (known to all as “Paddy”) passed away suddenly this morning at the age of 64. I believe he suffered a heart attack at his home in Pune.

Paddy was not only a prolific researcher, with over 300 articles and many books to his name, but also a very gifted public speaker. Although we met and chatted a few times I never really got to know Paddy personally, but I shall remember him best for the many wonderful lectures I heard him give, at conferences and in seminars, the first being at Sussex when I was a graduate student there ay back in the 1980s.

The sudden death of such a highly esteemed colleague and friend has shocked his family and circle of friends, as well as the physics community in India, and is sure to have a similar effect around the world as news travels. Paddy travelled widely and had collaborators across the globe, including in the United Kingdom and United States.

All I can do here is to offer my sincere condolences to his family, friends, scientific colleagues who are grieving now, and for whom his loss will be irreparable.

Rest in peace, Thanu Padmanabhan (“Paddy”) (1957-2021).

New Publication at the Open Journal of Astrophysics

Posted in Open Access, The Universe and Stuff with tags , , , , , , on September 16, 2021 by telescoper

Time to announce another publication in the Open Journal of Astrophysics. This one is the ninth paper in Volume 4 (2021) and the 40th in all.

The latest publication is entitled Black Hole Shadow Drift and Photon Ring Frequency Drift. The authors are Emmanuel Frion (Helsinki), Leonardo Giani (Queensland) and  Tays Miranda (Jyväskylä).

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

You can click on the image to make it larger should you wish to do so. You can find the arXiv version of the paper here. This one is also in the folder marked Cosmology and Nongalactic Astrophysics; although primarily in general relativity and quantum cosmology (gr-qc) it is cross-listed in astro-ph so it eligible for publication with us.

The end of the summer has been heralded by the arrival at OJAp HQ of a number of revised versions so I expect to be publishing a few more papers in the next few weeks!

New Publication at the Open Journal of Astrophysics

Posted in Open Access, The Universe and Stuff with tags , , , , , , on August 19, 2021 by telescoper

Time to announce another publication in the Open Journal of Astrophysics. This one is the eighth paper in Volume 4 (2021) and the 39th in all.

The latest publication is entitled A Detailed Description of the CAMSPEC Likelihood Pipeline and a Reanalysis of the Planck High Frequency Maps. The authors are George Efstathiou and Steven Gratton of the Kavli Institute for Cosmology at the University of Cambridge.

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

You can click on the image to make it larger should you wish to do so. You can find the arXiv version of the paper here. This one is also in the folder marked Cosmology and Nongalactic Astrophysics.

This is a long and detailed paper, running to 92 pages in PDF form. Our Editorial process relies on referees being willing to volunteer their time to read and comment on submissions and this one in particular required a great deal of effort. I am always grateful to referees but in this case I am even more grateful than usual the diligence displayed during and the many useful comments received. I know who our reviewers are and they know who they are, but shall remain anonymous!

Happy 30th Birthday to the arXiv!

Posted in Biographical, Open Access, The Universe and Stuff with tags , , , on August 14, 2021 by telescoper

I was reminded yesterday that today, 14th August, is the 30th anniversary of the start of the arXiv so I thought I’d send a quick birthday greeting to mark the occasion. In case you weren’t aware, arXiv is a free distribution service and an open-access archive containing (currently) 1,928,825 scholarly articles in the fields of physics, mathematics, computer science, quantitative biology, quantitative finance, statistics, electrical engineering and systems science, and economics.

There was a precursor to the arXiv in the form of an email distribution list for preprints, but arXiv proper started on 14th August 1991. It was based at Los Alamos National Laboratory (LANL) with a mirror site in SISSA (Trieste) that was used by those of us in Europe. In the beginning, arXiv was quite a small-scale thing and it wasn’t that easy to upload full papers including figures. In fact the SISSA system was run from a single IBM 386 PC (called “Babbage”). As it expanded, the running of arXiv was taken over Cornell University. You can read more about the history here.

You have to remember that journals didn’t generally have electronic submission in those days: you had to send paper manuscripts in the post to the Editorial office. Likewise many of us carried on sending out paper preprints for some time after the arXiv was set up. Younger researchers should be grateful they don’t have to put up with the absolute chore of producing papers the old-fashioned way!

The astrophysics section of arXiv (“astro-ph”) started in April 1992. Although astrophysicists generally were quick to latch on to this new method of distributing preprints, it took me a little time to get onto arXiv: my first papers did not appear there until February 1993; my first publication was in 1986 so there are quite a few of my early papers that aren’t on arXiv at all. In 1993 I was working at Queen Mary & Westfield College (as it was then called). I was working a lot with collaborators based in Italy at the time and they decided to start posting our joint papers on arXiv. Without that impetus it would have taken me much longer to get to grips with it.

In case you’re interested, my first paper to appear on the arXiv was this one on 23rd February 1993 but it was followed a day later by two others, this one and that one. I don’t remember very well, but this was an exercise in catching up and all three of those papers were actually published in journals before we put them on arXiv. It was only later that we got into the habit of posting papers on arXiv at the same time as submitting to a journal, which I think is the best way to do it!

The Open Journal of Astrophysics would not have been possible without the arXiv but in a wider sense the astrophysics community has a very great deal to thank the arXiv for, but remember that it is funded by donations and is run on a shoestring. If you agree that it’s a tremendously useful asset for your research then please consider making a donation.

New Publication at the Open Journal of Astrophysics

Posted in Open Access, The Universe and Stuff with tags , , , on August 13, 2021 by telescoper

Back from my short trip, I now have time to announce another publication in the Open Journal of Astrophysics. This one was published at the end of last month, but owing to the holiday season there was a delay in activating the DOI and registering the metadata  so I have delayed posting about it until just now. It is the seventh paper in Volume 4 (2021) and the 38th in all.

The latest publication is entitled A Differentiable Model of the Assembly of Individual and Populations of Dark Matter Halos. The authors are Andrew P. Hearin,  Jonás Chaves-Montero, Matthew R. Becker and Alex Alarcon, all of the Argonne National Laboratory.

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

You can click on the image to make it larger should you wish to do so. You can find the arXiv version of the paper here. This one is also in the folder marked Cosmology and Nongalactic Astrophysics.

We’ve had a bit of a surge in submissions over the last few weeks – no doubt due to authors using their “vacation” to finish off papers. August is not the best month for finding referees, but we’ll do our best to process them quickly!