Archive for protocluster

Two New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , on June 15, 2024 by telescoper

It’s Saturday morning in Barcelona, 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 47 and the total published by OJAp up to 162. We actually accepted four papers last week, but so far only two final versions have appeared on the arXiv.

The first paper of the most recent pair – published on  Friday 14th June – is “Spectroscopic Confirmation of an Ultra-Massive Galaxy in a Protocluster at z ~ 4.9″ . The author list has a strong University of California flavour: Stephanie M. Urbano Stawinski (UC Irvine), M. C. Cooper (UC Irvine), Ben Forrest (UC Davis) , Adam Muzzin (York University, Canada), Danilo Marchesini (Tufts University), Gillian Wilson (UC Merced), Percy Gomez (Keck Observatories, USA), Ian McConachie (UC Riverside), Z. Cemile Marsan (York University, Canada), Marianna Annuziatella (Centro de Astrobiología CSIC-INTA, Spain) and Wenjun Chang (UC Riverside).

This paper presents an investigation of a cluster system involving a massive galaxy using Keck spectroscopy with determination of its redshift and star formation properties. The results pose a challenge for theorists. The paper is in the folder marked Astrophysics of Galaxies.

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, also published on Friday 14th June and has the title “Boil-off of red supergiants: mass loss and type II-P supernovae” by Jim Fuller (Caltech) and  Daichi Tsuna (Caltech, USA and University of Tokyo, Japan). This one, which is in the folder marked Solar and Stellar Astrophysics, discusses A new model for stellar mass loss which predicts that low-mass red supergiants lose less mass than commonly assumed, while high-mass red supergiants lose more.

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. Will we reach 50 for 20204 next week? Tune in next Saturday to find out!

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A proto-cluster at z ~ 8!

Posted in The Universe and Stuff with tags , , , , on April 26, 2023 by telescoper
Blow-ups of the seven galaxies with spectroscopic redshifts, shown together with their positions near the line of sight to a foreground cluster.

I missed the paper containing this impressive picture when it first appeared on the arXiv, the primary source for astrophysics and cosmology research, but fortunately it has now been published on a secondary site, Astrophysical Journal Letters, with an accompanying press release so I can now do a quick post about it.

The article concerned, with lead author Takahiro Morishita of the California Institute of Technology (Caltech) et al. describes the detection using JWST of an apparent proto-cluster – seven galaxies in close proximity – at redshift z = 7.88. Here is the abstract:

Although only seven galaxies are identified, this does look like the very early stages of formation of an object that will grow into a giant galaxy cluster by the present epoch. The redshift of this progenitor corresponds to a stage of the Universe just 650 million years or so after the Big Bang, compared with the current age of about 14 billion years. As the abstract says, we would need to know more about other possible constituent galaxies and their motions to be sure, but it looks like a baby destined to grow into a monster…

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