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<blockquote style="position: relative; padding-left: 55px;"><section><a href="https://astrodon.social/users/kellylepo/statuses/111053356035901558">Kelly Lepo (kellylepo@astrodon.social)'s status on Friday, 15-Sep-2023 02:19:21 JST</a><a href="https://astrodon.social/@kellylepo" title="kellylepo@astrodon.social"><img src="https://gnusocial.jp/avatar/28639-48-20221116180105.webp" width="48" height="48" alt="Kelly Lepo" style="position: absolute; left: 0; top: 0;">Kelly Lepo</a><div><a href="https://astrodon.social/@kellylepo/111052843352137622" rel="in-reply-to">in reply to</a></div></section><article><p>Results out from Adam Riess, the Hubble Tension remains after observations of cepheid variable stars with JWST's clearer near-infrared view.</p><p>Measurements of the local value of the expansion rate of the universe (from the cosmic distance ladder) disagree with the rate you predict from measurements made in the early universe (CMB). </p><p>Blog post:<br><a href="https://webbtelescope.org/contents/early-highlights/webb-confirms-accuracy-of-universes-expansion-rate-measured-by-hubble" rel="nofollow noreferrer">https://webbtelescope.org/contents/early-highlights/webb-confirms-accuracy-of-universes-expansion-rate-measured-by-hubble</a><br><a href="https://astrodon.social/tags/JWSTYearOne" rel="tag">#JWSTYearOne</a></p></article><footer><a rel="bookmark" href="https://gnusocial.jp/conversation/2052104#notice-4043187">In conversation</a><time datetime="2023-09-15T02:19:21+09:00" title="Friday, 15-Sep-2023 02:19:21 JST">about a year ago</time> <span>from <span><a href="https://astrodon.social/@kellylepo/111053356035901558" rel="external" title="Sent from astrodon.social via ActivityPub">astrodon.social</a></span></span><a href="https://astrodon.social/@kellylepo/111053356035901558">permalink</a><h4>Attachments</h4><ol><li><label><a rel="external" href="https://gnusocial.jp/attachment/1521046">Baseline Fit: ~3200 Cepheids, ~300 SN, non-diagonal covariance 
5 free params.
Three scatter plots graphs, showing a linear correlation between variables. The graphs are lined up from bottom left to top right.  A line continues through all of them. The graphs are:  
Geometry —&gt; Cepheids 
Cepheids —&gt; Type Ia Supernovae  
Type Ia Supernovae —&gt; redshift(z)</a></label><br><a href="https://cdn.masto.host/astrodonsocial/media_attachments/files/111/053/348/249/593/814/original/b3d6ca7aebd978f8.png" rel="external">https://cdn.masto.host/astrodonsocial/media_attachments/files/111/053/348/249/593/814/original/b3d6ca7aebd978f8.png</a></li><li><label><a rel="external" href="https://gnusocial.jp/attachment/1521047">What Can JWST Do? Provide an Uncrowded View! 
* NIR Crowding (from red giants) not a systematic (bias removed using artificial stars) but can be largest source of PL scatter (i.e., statistical noise). 
HST: Passed Six validation tests of backgrounds/crowding (Riess et al. 2022)Graphic titled “Uncrowding Cepheids in the Near-Infrared.” Left: Colorful image of a spiral galaxy is labeled “NGC 5584 (Webb NIRCam + Hubble WFC3).” Part of a spiral arm is outlined with a box. Inside the box is a solid red circle. Middle: Set of two diagrams illustrating zoomed-in views of the boxed region. Top diagram shows Hubble pointing toward a large transparent box. Long edge of the base is labeled “depth.” Box contains numerous overlapping, blue-green spheres of different sizes, with a red sphere near the middle. Bottom diagram shows Webb pointing toward an almost identical box. Spheres in this box are significantly smaller and there is less overlap. The red sphere is labeled “Cepheid.” Right: Two square grayscale images. Top is labeled “HST WFC3-IR.” Bottom labeled “JWST NIRCAM.” Pixels in the top image are noticeably larger than those in the bottom image. Black spots in the bottom image are smaller, more distinct, and more numerous.</a></label><br><a href="https://cdn.masto.host/astrodonsocial/media_attachments/files/111/053/351/088/419/924/original/9a32c904ed5b70e1.png" rel="external">https://cdn.masto.host/astrodonsocial/media_attachments/files/111/053/351/088/419/924/original/9a32c904ed5b70e1.png</a></li><li><label><a rel="external" href="https://gnusocial.jp/attachment/1521048">JWST vs HST PLRs: Cepheids in NGC 5584, N4258, Ap], accepted, arXiv:2307.15806 
* JWST scatter 2.5 times less than HST at 1.5 microns, excellent agreement of intercepts . 
Photometry (Dr. Gagandeep Anand @ STScI) w/ Dolphot (ERS, JWST edition).
Two scatter plots of magnitude vs the log of the period. Grey points are HST, red points are JWST. Both sets of points show a linear trend. The HST points have more scatter. You can see this in an inset image, where the stars seen in HST are much fuzzier than JWST.</a></label><br><a href="https://cdn.masto.host/astrodonsocial/media_attachments/files/111/053/352/227/487/599/original/d99fed98b5154018.png" rel="external">https://cdn.masto.host/astrodonsocial/media_attachments/files/111/053/352/227/487/599/original/d99fed98b5154018.png</a></li><li><label><a rel="external" href="https://gnusocial.jp/attachment/1521049">Conclusions
Discrepancy is 5 sigma, ~10 years, No precise Late &lt; Early, very robust 
* Exhaustive study of systematics, variations, we see no internal Inconsistencies, excess noise, etc 
*Tests inconsistent with dust, metallicity, crowding as explanations.Graph showing the measured expansion rate of the universe over time, with shaded areas marking error bars. Plank CMB is green. SN Ia-Cepheids distance ladder is grey. The error bars go down over time. and the points diverge, showing the continuing Hubble tension. 
Insert graph shows Hubble constant measurements in the Early Universe and Direct measurements. The averages are different.</a></label><br><a href="https://cdn.masto.host/astrodonsocial/media_attachments/files/111/053/355/129/545/896/original/28467278cdd1dc78.png" rel="external">https://cdn.masto.host/astrodonsocial/media_attachments/files/111/053/355/129/545/896/original/28467278cdd1dc78.png</a></li><li><label><a rel="external" href="https://gnusocial.jp/attachment/1521050">Untitled attachment</a></label><br></li></ol></footer></blockquote>

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Kelly Lepo (kellylepo@astrodon.social)'s status on Friday, 15-Sep-2023 02:19:21 JST Kelly Lepo
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Results out from Adam Riess, the Hubble Tension remains after observations of cepheid variable stars with JWST's clearer near-infrared view.
Measurements of the local value of the expansion rate of the universe (from the cosmic distance ladder) disagree with the rate you predict from measurements made in the early universe (CMB).
Blog post:
https://webbtelescope.org/contents/early-highlights/webb-confirms-accuracy-of-universes-expansion-rate-measured-by-hubble
#JWSTYearOne
In conversationabout a year ago from astrodon.socialpermalink
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