martincidmagJun 11

Webb measured a 13-billion-year-old black hole — it formed before its galaxy

https://www.martincid.com/science/black-hole-formed-before-galaxy-abell2744-2/

#Abell2744Qso1 #GalaxyFormation #RobertoMaiolino

Webb measured a 13-billion-year-old black hole — it formed before its galaxy

Astronomers have directly measured a supermassive black hole from just 700 million years after the Big Bang. It is two-thirds as massive as the entire galaxy su

Martin Cid Magazine
Bible Science ForumJan 11, 2016

Changing-Look Quasars

Figure 1a: The quasar 3C 273, which resides in a giant elliptical galaxy in the constellation of Virgo. Credit: ESA/Hubble & NASA

How do they fit into a biblical creationist model?

Quasars are very high redshift astronomical objects with broad emission line (BEL) spectra. The latter is very different to that in the usual humdrum galaxies. This means the objects redshifts and BEL spectra can be used to identify them. And because of their high redshifts they are assumed to be very distant, very luminous active galaxies with super-massive black holes at their hearts, powering them to emit prodigious amounts of radiation over all wave-bands of the electromagnetic spectrum.

Figure 1b: Spectra of quasar 3C 273 compared to the star Vega. Spectral lines are shifted towards the red end of the spectrum, from which its distance is determined using the standard LCDM cosmology.

Most of the high redshift objects in the universe are quasars. The redshifts of galaxies and quasars when interpreted within big bang cosmology—the greater the redshift the greater the distance—means that the most distant objects are seen at a time when the Universe was youngest.1

Following big bang thinking, quasars are then considered to be just galaxies in some early stage of development—back closer in time to the big bang—than the usual spiral and elliptical galaxies we might see with much lower redshifts. The quasar 3C 273, shown in Fig. 1a, the first to be identified (discovered in the early 1960s by astronomer Allan Sandage), has been shown to reside in a giant elliptical galaxy in the constellation of Virgo. According to standard cosmology its redshift puts it at a distance of 2.5 billion light-years from Earth.

Quasar to galaxy transitions

According to the big bang theory, how long should a quasar remain in the form of a quasar before transitioning into a normal galaxy and how long should that transition take? Quite obviously the answer to that question depends on one having a correct understanding of what quasars actually are and an accurate model describing their evolution. It would be no underestimate to state that an accurate model for galaxy formation, let alone a transition from a quasar to a normal field galaxy, is far from being known. The formation of a galaxy alone requires the invoking of a very large dark matter content, and often ‘jumping over’ the important details of star formation just to obtain something that looks like a galaxy. This means that there are physical laws in this Universe that create barriers in computer simulations preventing the formation of stars and hence galaxies. It is these that must be ‘jumped over’ in order that the simulations may proceed.2

We can assume that quasars have masses comparable to that of most galaxies. From that is follows then that naturalistic changes—that is, uniformitarian changes—can be expected to be of the order of a billion years.3 Without any real model for the changes expected in quasars, it may not be too unreasonable to expect any changes in their luminosity to be over uniformitarian timescales, and fuelled by growth of their supermassive black-holes, as some propose.

By contrast, according to the Genesis 1 narrative, God took one 24-hour day to create all astronomical objects, therefore we expect at creation that the youngest sources (which could include quasars) have very quickly changing observable features, such as luminosity. Yet very rapid changes, even down to timescales of days and weeks, in the observed luminosity of quasars have been recorded.4,5 One suggestion is that those variations are caused by microlensing6 and another is obscuration by dust but these mechansims are considered to be too long.7 Another is the rapid consumption of a passing star or gas and dust by the central supermassive black hole. Such proposals are offered because changes on such short timescales are not expected from the growth of the alleged supermassive black-holes at the heart of the quasars.

Changing-look quasars

Now we read in an online news report8 that astronomers think that they have detected a dozen quasars in a disappearing act—the so-called “changing-look quasars.” Or they have been caught transitioning into their quiescent and dimmer counterparts—galaxies with starving black holes at their cores. This fact has left astronomers asking whether these objects are shutting down permanently or simply flickering out for the time being.

Last year Stephanie LaMassa from NASA Goddard Space Flight Center (then at Yale University) discovered the greatest change in luminosity ever detected in a quasar. She was digging through data from the Sloan Digital Sky Survey when she found that a quasar had dimmed in brightness by a factor of six in just 10 years. Its spectrum changed, too, from that of a classic quasar to a regular galaxy.8 (my emphasis added)

Figure 2: The image shows an artist’s conception of the ‘changing-look quasar’ as is appeared in early 2015. The glowing blue region shows the last of the gas being swallowed by the central black hole as it shuts off. The spectrum is the previous one obtained by the SDSS in 2003. Credit: Dana Berry / SkyWorks Digital, Inc.; SDSS collaboration.

Because astronomers believe in the very long time scale big bang paradigm they are forced to suggest any rapid dimming in the luminosity of any quasar must be either a transient effect or the very rare chance of observing the fuel exhausted from a supermassive black hole.  One report states that,

“Astronomers can’t find any sign of the black hole at the center of the quasar SDSS J1011+5442, and they couldn’t be happier.”9

In the case of this quasar (see Fig. 2) it is alleged that,

“… over the past ten years, it appears to have swallowed all the gas in its vicinity. With the gas fallen into the black hole, astronomers from the Sloan Digital Sky Survey (SDSS) were unable to detect the spectroscopic signature of the quasar, which now appears as an otherwise normal galaxy.”9 (my emphasis added)

The dimming was very significant and now appears like a normal humdrum galaxy.

“The difference was stunning and unprecedented,” said John Ruan of the University of Washington, lead author of a related paper ….. “The hydrogen-alpha emission dropped by a factor of 50 in less than twelve years, and the quasar now looks like a normal galaxy.” The change was so great that throughout the SDSS collaboration and astronomy community, the quasar became known as a “changing-look quasar.”9 (my emphasis added)

However, one of the newly discovered rapidly dimming quasar did re-brighten.

“And one of the 12 newly discovered objects did not just disappear but reappear. Krolik thinks that this lonely quasar blazed back into existence for the same reason that it flickered out: a variation in the gas and dust flowing onto the black hole.”8 (my emphasis added)

Certainly it is possible that the standard interpretation for quasars as AGNs10 powered by a supermassive black-hole is one possible explanation. The next step then will be to see if any of the other newly discovered dozen or so quasars re-brighten over the coming years.

A different explanation

A different explanation is one consistent with the work of the late Halton Arp11 where he suggested that quasars are born from the hearts of active parent galaxies. Over time, which he had no measure of, the ejected quasars transitioned from active highly luminous high redshift objects with BEL line spectra to the usual field galaxies with much lower redshifts and typical spectra.  This is illustrated in Fig. 3. Quasars are ejected in opposite directions from the nucleus of an active galaxy and over time they change their internal state including redshift, which decreases with finite discrete steps towards the commonly observed low redshift in field galaxies. Thus quasars and active galactic nuclei become normal galaxies.

Figure 3: Arp’s model of ejection of quasars from active parent galaxies and their eventual change to normal galaxies. Reproduced from Ref. 11 after Arp’s original in his book “Seeing Red.”

Apparently the idea that quasars or active galactic nuclei could become inactive is not controversial in the big bang universe. But the expected timescale is not less than tens of thousands of years. What LaMassa and her colleagues doubted was that a quasar could go from active to inactive in just 10 years.  But this is what these newly discovered rapidly dimming quasars have established. Rapid changes in the emission properties of the quasars, on timescales very much in line with a creation scenario, are observed. Even their spectra changing from that of a classic quasar to a regular galaxy.9

A biblical creation explanation

So this discovery is consistent with a creation scenario where we expect that processes in astronomical sources to be well less than seven thousand years. In the case of a creation process of galaxies formed from AGNs—the parent galaxies—and the ejected galaxies in the form of quasars, it would be essential that the quasars (at least some of them) have changed to normal humdrum galaxies in a period less than the time since Creation, that is less than about six thousand years.

However, it is also expected that many galaxies were created in their current forms, but if Arp’s evidence for quasars and active galactic nuclei transitioning to normal galaxies is correct, then this is what would be expected in the biblical creation model. Here we have an opportunity to see if these rapidly dimmed quasars, remain dim or re-brighten. Time will tell.

References

  • This claim I dispute as there is evidence that puts this idea in doubt.  There is strong evidence, even in the very large galaxy surveys that suggests a very high probability of high redshift quasars being associated with low redshift parent galaxies.
  • Hartnett, J.G., Stars just don’t form naturally—‘dark matter’ the ‘god of the gaps’ is needed, September 1, 2015.
  • Back of the envelope calculation for the formation of a typical sized galaxy and hence quasar from the free collapse of a proto-Galactic cloud is of order 1 billion years. See B.W. Carroll & D.A. Ostlie, An Introduction to Modern Astrophysics, 1st Edition. pp. 1074-75, 1996.
  • M.R.S. Hawkins, Time dilation and quasar variability, Astrophys. J. 553:L97–L100, 2001.
  • M.R.S. Hawkins, On time dilation in quasar light curves, MNRAS 405:1940–1946, 2010.
  • When a quasar is sufficiently aligned with a massive compact foreground object the bending of light due to its gravitational field is distorted, resulting in an observable magnification. The timescale of the transient brightening depends on the mass of the foreground object as well as on the relative proper motion between the background ‘source’ and the foreground ‘lens’ object.
  • C.L. MacLeod, et al., A systematic search for changing-look quasars in SDSS, MNRAS, 457(1): 389-404, 2016.
  • S. Hall, The Case of the Disappearing Quasars, Scientific American, November 23, 2015
  • J. Raddick, The Case of the Missing Quasar, SDSS, January 6, 2015.
  • AGN = Active Galactic Nucleus
  • J.G. Hartnett, The heavens declare a different story, May 3, 2014; Journal of Creation 17(2):94–97, August 2003.

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    In the DarkMay 16

    Weekly Update from the Open Journal of Astrophysics – 16/05/2026

    It’s Saturday once again, so time for another update of activity at the Open Journal of Astrophysics. Since the last update we have published a further five papers, bringing the number in Volume 9 (2026) to 104 and the total so far published by OJAp up to 552. It took us until late July to pass 100 last year.

    I will continue to include the posts made on our Mastodon account (on Fediscience) to encourage you to visit it. Mastodon is a really excellent service, and a more than adequate replacement for X/Twitter (which nobody should be using); these announcements also show the DOI for each paper.

    The first paper to report this week, published on Monday 11th May in the folder High-Energy Astrophysical Phenomena is “Triaxial magnetars as sources of fast radio bursts” by Jonathan I Katz (Washington University, USA). This paper suggests that the mysterious properties of Fast Radio Bursts (FRB) could be explained by triaxial magnetars, with their activity levels influenced by precessional time scales.

    The overlay for this paper is here

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

    https://fediscience.org/@OJ_Astro/116554775791392800

    The second paper for this week, published on Tuesday 12th May in the folder Astrophysics of Galaxies, is “The Abundance of Thin Dwarf Galaxies: a Challenge for Cosmological Simulations” by Jose Benavides & Laura V. Sales (UC Riverside, USA), Julio F. Navarro (U. Victoria, Canada), Simon D. M. White (MPA Garching, Germany), and Carlos S. Frenk, Kyle A. Oman & Shaun Cole (U. Durham, UK). Depending on mass up to 40% of galaxies are intrinsically flat, a fraction that numerical models of galaxy formation struggle to reproduce suggesting the models are incomplete.

    The overlay for this one is here:

    The official version of the paper can be found on arXiv here and the Fediverse announcement here:

    https://fediscience.org/@OJ_Astro/116560106342500157

    Next one up, the third paper of the week, also published on Tuesday 12th May but in the folder Cosmology and Nongalactic Astrophysics is “Cosmological peculiar velocities in general relativity” by Chris Clarkson (Queen Mary, University of London, UK) and Roy Maartens (U. Western Cape, South Africa). This paper refutes claims that the 1+3 covariant approach to cosmological perturbation theory predicts stronger growth of galaxy peculiar velocities, arguing that standard treatments are correct and fully relativistic.

    The overlay for this one is here:

    The final, accepted version can be found on arXiv here and the Mastodon announcement is here:

    https://fediscience.org/@OJ_Astro/116560224426499932

    The fourth paper this week, published on Wednesday May 13th “Possible evidence for a pair-instability supernova nature of ultra-early JWST sources” by Andrea Ferrara & Stefano Carniani (Scuola Normale Superiore, Pisa, Italy), Takahiro Morishita (California Institute of Technology, USA), and Massimo Stiavelli (Space Telescope Science Institute, USA). Published in the section Astrophysics of Galaxies. This paper argues that recent observations challenge early galaxy formation models, suggesting that the bright source, Capotauro, could be a supernova from a massive, metal-free star, not a luminous galaxy as initially thought.

    The overlay is here:

    The officially accepted version can be found on arXiv here and here is the Mastodon announcement:

    https://fediscience.org/@OJ_Astro/116566147448743997

    The fifth and final article of this week was also published on Wednesday 13th May but in the folder Cosmology and Nongalactic Astrophysics. The title is “Evolving and interacting dark energy: photometric and spectroscopic synergy with DES Y3 and DESI DR2” and it is by Maria Tsedrik and Benjamin Bose (University of Edinburgh, UK). The study investigates the Dark Scattering interacting dark energy scenario, using data from various sources. Results show no evidence of dark-sector interaction and a preference for the Chevallier-Polarski-Linder parametrisation.

    The overlay is here:

    You can find the authorized version of this paper on arXiv here and the Fediverse announcement is here:

    https://fediscience.org/@OJ_Astro/116566165139100860

    And that concludes this week’s update. I’ll do another next Saturday.

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    In the DarkMay 2

    Weekly Update from the Open Journal of Astrophysics – 02/05/2026

    Here we are, on schedule, with another update of activity at the Open Journal of Astrophysics. Since the last update we have published a further seven papers, bringing the number in Volume 9 (2026) to 94 and the total so far published by OJAp up to 542. I checked the corresponding update for last year (on 3rd May 2025), and we’ve had an increase from 54 to 94 in papers published (about 74%) between the first four months of 2025 and the first four months of 2026.

    I will continue to include the posts made on our Mastodon account (on Fediscience) to encourage you to visit it. Mastodon is a really excellent service, and a more than adequate replacement for X/Twitter (which nobody should be using); these announcements also show the DOI for each paper.

    The first paper to report this week is “DESI-DR1 3 × 2-pt analysis: consistent cosmology across weak lensing surveys” by Anna Porredon (CIEMAT, Madrid, Spain) and 72 others (DESI Colllaboration). This paper was published on Tuesday 28th April in the folder Cosmology and Nongalactic Astrophysics. This paper presents a joint cosmological analysis of galaxy clustering and gravitational lensing observations, providing consistent constraints on cosmological parameters. The analysis also introduces a new blinding procedure to prevent confirmation bias. See this post for news of an important DESI milestone.

    The overlay for this paper is here

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

    https://fediscience.org/@OJ_Astro/116480407578621011

    The second paper for this week, also published on Tuesday 28th April but in the folder High-Energy Astrophysical Phenomena is “Masers and Broad-Line Mapping Favor Magnetically-Dominated AGN Accretion Disks” by Philip F. Hopkins (Caltech, USA), Dalya Baron (Stanford U., USA) and Joanna M. Piotrowska (Caltech). This one presents a new constraint on supermassive black hole accretion disks physics, suggesting that outer regions are likely in a ‘hyper-magnetized’ state, as thermal or radiation pressure models appear inconsistent.

    The overlay for this one is here:

    The official version of the paper can be found on arXiv here and the Fediverse announcement here:

    https://fediscience.org/@OJ_Astro/116480505354195181

    Next one up, the third paper of the week, is “Galaxy mergers and disk angular momentum evolution: stellar halos as a critical test” by Eric F. Bell (U. Michigan, Ann Arbor, USA), Richard D’Souza (Vatican Observatory), Monica Valluri & Katya Gozman (U. Michigan). This was published on Wednesday 29th April in the folder Astrophysics of Galaxies. The paper argues that satellite accretion impacts the angular momentum evolution of galaxies, often causing significant reorientation. This process is detectable in Milky Way-mass galaxies so the idea is testable observationally.

    The overlay for this one is here:

    The final, accepted version can be found on arXiv here and the Mastodon announcement is here:

    https://fediscience.org/@OJ_Astro/116486649450860283

    The fourth paper this week, published on Thursday April 30th, is “Time-Dilation Methods for Extreme Multiscale Timestepping Problems” by Philip F. Hopkins and Elias R. Most (Caltech, USA). This paper is in the folder Instrumentation and Methods for Astrophysics: it presents a new method for astrophysical simulations that modulates time evolution with a variable dilation/stretch factor, improving efficiency and accuracy in modeling processes across different scales.

    The overlay is here:

    The finally accepted version of this paper can be found here and the Mastodon announcement follows:

    https://fediscience.org/@OJ_Astro/116492226856595031

    The fifth article of this week was also published on Thursday 30th April, but in the folder Astrophysics of Galaxies. The title is “Cosmic Rays on Galaxy Scales: Progress and Pitfalls for CR-MHD Dynamical Models” and the author is Philip F. Hopkins (Caltech, USA) who has three papers featured this week. The paper presents an overview of cosmic ray (CR) modeling, highlighting its influence on galactic physics and star formation. It addresses previous modeling errors and presents new methods for full-spectrum dynamics.

    The overlay is here:

    You can find the authorized version of this paper on arXiv here and the Fediverse announcement is here:

    https://fediscience.org/@OJ_Astro/116492282488422075

    The sixth paper of the week is “Baryonification III: An accurate analytical model for the dispersion measure probability density function of fast radio bursts” by MohammadReza Torkamani (Universität Bonn, Germany) and 8 others based in Germany, Switzerland, UK and Sweden. This article was also published on Thursday April 30th in the folder Cosmology and Nongalactic Astrophysics. It presents a framework for predicting dispersion measures of fast radio bursts using the baryonification model, providing a cost-effective alternative to hydrodynamical simulations. The model’s accuracy is validated through full numerical simulations. The overlay is here:

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

    https://fediscience.org/@OJ_Astro/116492403170125062

    Seventh and finally for this week we have “The stellar and dark matter distributions in early-type galaxies measured by stacked weak gravitational lensing” by Momoka Fujikawa and Masamune Oguri (Chiba University, Japan). This study uses weak gravitational lensing to investigate stellar mass and dark matter density in red galaxies, suggesting a stronger feedback effect than current simulations predict. This was published on Friday 1st May 2026 in the folder Astrophysics of Galaxies. The overlay is here:

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

    https://fediscience.org/@OJ_Astro/116497987401632687

    And that concludes this week’s update. I’ll do another one at the end of next week. Will Vol. 9 have reached a hundred by then?

    P.S. Just a reminder that, thanks to the efforts of a member of our Editorial Board, the Open Journal of Astrophysics now has a Wikipedia page.

    #32PtAnalysis #ActiveGalacticNuclei #AGN #arXiv250907104v2 #arXiv251009756v2 #arXiv251209342v2 #arXiv251215960v3 #arXiv260106253v2 #arXiv260118784v2 #arXiv260424965v1 #AstrophysicsOfGalaxies #baryonification #ComputationalAstrophysics #cosmicRays #CosmologyAndNonGalacticAstrophysics #DarkEnergySpectroscopicInstrument #DESI #DiamondOpenAccess #DiamondOpenAccessPublishing #DispersionMeasures #fastRadioBursts #galacticCosmicRays #galaxyEvolution #galaxyFormation #galaxyMergers #HighEnergyAstrophysicalPhenomena #InstrumentationAndMethodsForAstrophysics #magnetohydrodynamics #masers #MilkyWay #OpenAccess #OpenAccessPublishing #SolarAndStellarAstrophysics #SolarCorona #supermassiveBlackHoles #VeraCRubinObservatory #weakGravitationalLensing #wikipedia
    adsdailyApr 28

    📄 The Rise of the Galactic Empire: Ultraviolet Luminosity Functions at …

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    Pérez-González, Pablo G. et al. (2025) · The Astrophysical Journal
    Reads: 559 · Citations: 71
    DOI: 10.3847/1538-4357/adf8c9

    🔗 https://ui.adsabs.harvard.edu/abs/2025ApJ...991..179P/abstract

    #Astronomy #Astrophysics #Galaxies #DarkUniverse #GalaxyFormation

    The Rise of the Galactic Empire: Ultraviolet Luminosity Functions at z ∼ 17 and z ∼ 25 Estimated with the MIDIS+NGDEEP Ultra-deep JWST/NIRCam Data Set

    We present a sample of six F200W and three F277W dropout sources identified as 16 < z < 25 galaxy candidates using the deepest JWST/NIRCam data to date (5σ depths ∼31.5 mag at ≥2 μm), provided by the MIRI Deep Imaging Survey and the Next Generation Deep Extragalactic Exploratory Public survey. We estimate ultraviolet (UV) luminosity functions and densities at z ∼ 17 and z ∼ 25. The number density of galaxies with absolute magnitudes of −19 < M<SUB>UV</SUB> < −18 at z ∼ 17 (z ∼ 25) is a factor of 4 (25) smaller than at z ∼ 12; the luminosity density presents a similar evolution. Compared to state-of-the-art galaxy simulations, we find the need for an enhanced UV-photon production at z = 17─25 in M<SUB>DM</SUB> = 10<SUP>8.5−9.5</SUP> M<SUB>⊙</SUB> dark matter halos, provided by an increase in the star formation efficiency at early times and/or by intense compact starbursts with enhanced emissivity linked to strong burstiness, low or primordial gas metallicities, and/or a top-heavy initial mass function. There are a few robust theoretical predictions for the evolution of galaxies above z ∼ 20 in the literature; however, the continuing rapid drop in the halo mass function would predict a more rapid evolution than we observe if photon production efficiencies remained constant. Our z > 16 candidates present mass-weighted ages around 30 Myr, and attenuations A(V) < 0.1 mag. Their average stellar mass is M<SUB>⋆</SUB> ∼ 10<SUP>7</SUP> M<SUB>⊙</SUB>, implying a stellar-to-baryon mass fraction around 10% if the emissivity increases with redshift, or significantly higher otherwise. Three candidates present very blue UV spectral slopes (β ∼ −3) compatible with Population III young (≲10 Myr) stars and/or high escape fractions of ionizing photons; the rest have β ∼ −2.5 similar to the z = 10─12 samples.

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    Des galaxies sans matière noir...
    AlcorNewsApr 27
    Galaxies sans matière noire: des observations JWST suggèrent que certains objets défient totalement les modèles standards de formation cosmique
    https://www.pourlascience.fr/sd/astrophysique/des-galaxies-sans-matiere-noire-defient-les-modeles-de-formation-galactique-29121.php
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    In the DarkApr 25

    Weekly Update from the Open Journal of Astrophysics – 25/04/2026

    So here we are again, on a Saturday morning, with another update of activity at the Open Journal of Astrophysics. Since the last update we have published a further five papers, bringing the number in Volume 9 (2026) to 87 and the total so far published by OJAp up to 535.

    I will continue to include the posts made on our Mastodon account (on Fediscience) to encourage you to visit it. Mastodon is a really excellent service, and a more than adequate replacement for X/Twitter (which nobody should be using); these announcements also show the DOI for each paper.

    The first paper to report this week is “Bayesian Cosmic Void Finding with Graph Flows” by Leander Thiele (U. Tokyo, Japan). This was published on Monday 20th April in the folder Cosmology and Nongalactic Astrophysics. The paper presents a method using a deep graph neural network to identify cosmic voids in sparse galaxy surveys, improving upon traditional deterministic algorithms by considering the problem’s probabilistic nature. The overlay is here:

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

    https://fediscience.org/@OJ_Astro/116435864086025246

    The second paper for this week, published on Wednesday 22nd April in the folder Astrophysics of Galaxies, is “Sifting for a Stream: The Morphology of the 300S Stellar Stream” by Benjamin Cohen (U. Chicago, USA) and 20 others distributed around the world. This study analyzes the morphology of the $300S$ stellar stream, revealing three density peaks, a possible gap, and a kink, suggesting significant influence from the Large Magellanic Cloud on its structure.

    The overlay for this one is here:

    The official version of the paper can be found on arXiv here and the Fediverse announcement here:

    https://fediscience.org/@OJ_Astro/116447005556180402

    Next one up, the third paper of the week, is “IRMaGiC: Extending Luminous Red Galaxy Selection into the Infrared with Joint Rubin Observatory’s Large Survey of Space Time and Roman’s High Latitude Imaging Survey” by Zhiyuan Guo & Chris. W. Walter (Duke U., USA) and Eli S. Rykoff (Stanford U., USA) on behalf of the LSST Dark Energy Science Collaboration. This was published on Wednesday April 22nd in the folder Cosmology and Nongalactic Astrophysics. The paper introduces IRMaGiC, an algorithm that improves the selection and redshift estimation of Luminous Red Galaxies (LRGs) by incorporating infrared data, enhancing future cosmological surveys.

    The overlay for this one is here:

    The final, accepted version can be found on arXiv here and the Mastodon announcement is here:

    https://fediscience.org/@OJ_Astro/116447067337351283

    The fourth paper this week, published on Thursday April 23rd, is “The Diagnostic Temperature Discrepancy as Evidence for Non-Maxwellian Coronal Electrons” by Victor Edmonds (Final Stop Consulting, USA). This paper, in the folder Solar and Stellar Astrophysics, presents two methods of measuring electron temperature in the quiet solar corona yielding different results, suggesting non-Maxwellian electron velocity distributions may be responsible for the discrepancy.

    The overlay is here:

    The finally accepted version of this paper can be found here and the Mastodon announcement follows:

    https://fediscience.org/@OJ_Astro/116452775389963618

    The fifth and final paper for this week was published on Friday 24th April in the folder Astrophysics of Galaxies. The title is “Galaxy evolution in the post-merger regime. IV – The long-term effect of mergers on galactic stellar mass growth and distribution” by Sara L. Ellison (U. Victoria, Canada) and Leonardo Ferreira (Universidade Federal do Rio Grande, Brazil). This study uses a large sample of post-merger galaxies to demonstrate that galaxy mergers trigger significant and extended stellar mass growth in their central regions, independent of stellar population modelling.

    The overlay is here:

    You can find the authorized version of this paper on arXiv here and the Fediverse announcement is here:

    https://fediscience.org/@OJ_Astro/116458316824739014

    The overlay for this one is here:

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

    https://fediscience.org/@OJ_Astro/116458316824739014

    And that concludes this week’s update. I’ll do another one at the end of next week.

    P.S. Thanks to the efforts of a member of our Editorial Board, the Open Journal of Astrophysics now has a Wikipedia page.

    #300SStellarStream #arXiv250621410v2 #arXiv251121512v2 #arXiv260114554v2 #arXiv260214630v2 #arXiv260310040v3 #AstrophysicsOfGalaxies #BayesianMethods #CosmicVoids #CosmologyAndNonGalacticAstrophysics #DiamondOpenAccess #DiamondOpenAccessPublishing #EarthAndPlanetaryAstrophysics #GAIA #galaxyEvolution #galaxyFormation #galaxyMergers #InstrumentationAndMethodsForAstrophysics #IntergalacticMedium #IRMaGiC #LargeMagellanicCloud #LSST #LSSTDarkEnergyScienceCollaboration #MilkyWay #OpenAccess #OpenAccessPublishing #SolarAndStellarAstrophysics #SolarCorona #VeraCRubinObservatory #wikipedia
    Scientific WorldApr 19
    Discover how vast cosmic voids — the universe’s largest empty regions — influence galaxy formation and ripple through space-time as gravitational waves. Explore cutting-edge astrophysics uncovering the hidden role of emptiness in shaping cosmic evolution.
    #CosmicVoids #GalaxyFormation #GravitationalWaves #Astrophysics
    https://www.scientificworldinfo.com/2026/04/cosmic-voids-affect-galaxy-formation-and-gravitational-waves.html
    Do Cosmic Voids Affect Galaxy Formation and Gravitational Waves?

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    In the DarkApr 18

    Weekly Update from the Open Journal of Astrophysics – 18/04/2026

    It is Saturday morning, and therefore time for yet another update of activity at the Open Journal of Astrophysics. Since the last update we have published a further six papers, bringing the number in Volume 9 (2026) to 82 and the total so far published by OJAp up to 530.

    I will continue to include the posts made on our Mastodon account (on Fediscience) to encourage you to visit it. Mastodon is a really excellent service, and a more than adequate replacement for X/Twitter (which nobody should be using); these announcements also show the DOI for each paper.

    The first paper to report this week is “Beyond Spherical geometry: Unraveling complex features of objects orbiting around stars from its transit light curve using deep learning” by Ushasi Bhowmick & Shivam Kumaran (Indian Space Research Institute, Ahmedabad, India). This study uses deep neural networks to predict the shape of objects orbiting stars based on their transit light curves, demonstrating the potential to extract geometric information from these systems. It was published on Monday 13th April in the folder Earth and Planetary Astrophysics and the overlay can be seen here:

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

    https://fediscience.org/@OJ_Astro/116395992732332356

    The second paper for this week, also published on Monday 13th April but in the folder Astrophysics of Galaxies, is “statmorph-lsst: Quantifying and correcting morphological biases in galaxy surveys” by Elizaveta Sazonova (U. Waterloo, Canada) and an international cast of 18 others. This paper presents an investigation of potential biases in quantitative morphology metrics used in galaxy evolution studies, proposing two new measurements to resolve biases, and provides a related Python package (statmorph-lsst), which can be found here on github.

    The overlay for this one is here:

    The official version of the paper can be found on arXiv here and the Fediverse announcement here:

    https://fediscience.org/@OJ_Astro/116396069424189312

    Next one up, the third paper of the week, one of four published on Friday 17th April, is “Disentangling the galactic and intergalactic components in 313 observed Lyman-alpha line profiles between redshift 0 and 5” by Siddhartha Gurung-López (Universitat de València, Spain) and 7 others based in Spain and Germany. Published in the folder Astrophysics of Galaxies, this paper uses the zELDA package to analyze Lyman-alpha photons from star-forming galaxies, revealing IGM effects dominate Lyman-alpha observability at high redshifts, while galactic outflows become more important at lower z.

    The overlay for this one is here:

    The final, accepted version can be found on arXiv here and the Mastodon announcement is here:

    https://fediscience.org/@OJ_Astro/116418831864134501

    The fourth paper this week, also published on Friday 17th April is “Using Symbolic Regression to Emulate the Radial Fourier Transform of the Sérsic Profile for Fast, Accurate and Differentiable Galaxy Profile Fitting” by Tim B. Miller (Northwestern University, USA) and Imad Pasha (Yale University, USA). This one is published in the folder Instrumentation and Methods for Astrophysics: it develops an emulator for galaxy profile fitting in Fourier space, improving speed by 2.5 times with minimal accuracy loss, aiding in managing increasing data flow.

    The overlay is here:

    The finally accepted version of this paper can be found here and the Mastodon announcement follows:

    https://fediscience.org/@OJ_Astro/116418855010158656

    The fifth paper for this week is “The THESAN project: Lyman-alpha emitters as probes of ionized bubble sizes” by Meredith Neyer (MIT, USA) and 6 others based in the USA, Colombia, Canada, Japan and UK. The study uses THESAN simulations to explore how Lyman-alpha emitters (LAEs) trace ionized bubble sizes during the Epoch of Reionization, providing a framework for interpreting LAE surveys. This was published on Friday 17th April in the folder Astrophysics of Galaxies.

    The overlay for this one is here:

    You can find the authorized version of this paper on arXiv here and the Fediverse announcement is here:

    https://fediscience.org/@OJ_Astro/116418887225003954

    The sixth and final paper for this week is “Closed-Form Statistical Relations Between Projected Separation, Semimajor Axis, Companion Mass, and Host Acceleration” by Timothy D Brandt (Space Telescope Science Institute, USA). This was published on Friday 17th April in the folder Solar and Stellar Astrophysics. In this paper the author derives statistical relationships between radial velocity, a companion’s mass, and projected separation, useful for calculations requiring derivatives. The results are verified with empirical comparisons to existing literature.

    The overlay for this one is here:

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

    https://fediscience.org/@OJ_Astro/116418938017199814

    And that concludes this week’s update. I’ll do another one at the end of next week.

    P.S. Just a reminder, for those of you into LinkedIn, that we now have a page there.

    #arXiv250303824v4 #arXiv250820266v2 #arXiv250914875v2 #arXiv251018946v2 #arXiv251109644v2 #arXiv260114688v2 #AstrophysicsOfGalaxies #binaryStars #ComputationalAstrophysics #CosmologyAndNonGalacticAstrophysics #DiamondOpenAccess #DiamondOpenAccessPublishing #EarthAndPlanetaryAstrophysics #EpochOfReionization #galaxyFormation #GalaxyMorphology #galaxyProfiles #InstrumentationAndMethodsForAstrophysics #IntergalacticMedium #Ionization #LAEs #lightCurves #LSST #LymanAlphaEmitters #OpenAccess #OpenAccessPublishing #Orbits #SérsicProfile #SolarAndStellarAstrophysics #statmorphLsst #stellarHalos #strongGravitationalLensing #THESAN #zELDA