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<blockquote style="position: relative; padding-left: 55px;"><section><a href="https://astrodon.social/users/kellylepo/statuses/113853738150192595">Kelly Lepo (kellylepo@astrodon.social)'s status on Tuesday, 21-Jan-2025 01:35:05 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/113853738127238484" rel="in-reply-to">in reply to</a></div></section><article><p>One early project was to look for the Sunyaev-Zeldovich (SZ) effect, caused when background light from the Cosmic Microwave background scatters off of the hot gas in galaxy clusters.</p></article><footer><a rel="bookmark" href="https://gnusocial.jp/conversation/4411031#notice-8629064">In conversation</a><time datetime="2025-01-21T01:35:05+09:00" title="Tuesday, 21-Jan-2025 01:35:05 JST">about 4 months ago</time> <span>from <span><a href="https://astrodon.social/@kellylepo/113853738150192595" rel="external" title="Sent from astrodon.social via ActivityPub">astrodon.social</a></span></span><a href="https://astrodon.social/@kellylepo/113853738150192595">permalink</a><h4>Attachments</h4><ol><li><label><a rel="external" href="https://gnusocial.jp/attachment/3968303">The Sunyaev-Zeldovich (SZ) effect
Diagram shows a Microwave Background Photon entering Hot Cluster Gas. An Energetic Electron collides with the photon, producing a  Blue Shifted Microwave Photon, obervied by a telescope.
Photos of Sunyaev and Zeldovich, two friendly-looking middle-aged white men. One is in a leather jacket, tie and dress shirt. The other is in a suit.
Two important tSZ points:
1) tSZ effect is a measure of total thermal energy, so good mass proxy.
2) Surface brightness of the SZ effect is independent of redshift!
Sounds great, but the SZ effect is very low brightness and extended.</a></label><br><a href="https://media.astrodon.social/media_attachments/files/113/853/193/475/293/216/original/25a96b3017f83102.png" rel="external">https://media.astrodon.social/media_attachments/files/113/853/193/475/293/216/original/25a96b3017f83102.png</a></li><li><label><a rel="external" href="https://gnusocial.jp/attachment/3968304">Worked like a charm
• It worked very well.
• Imaged hundreds of clusters selected from various X-ray catalogs. Built special purpose "Sunyaev-Zel'dovich Array," eventually integrated into CARMA.
• Science results included initial SZ mass scalings, pressure profiles, constraints on the matter density parameter Ω™ and the Hubble constant Ho.
• But needed more sensitivity (faster mapping speed) to discover galaxy clusters in cosmological surveys (more on that later).
• Motivated using interferometry to measure intrinsic cosmic microwave background (CMB) anisotropy.
Image of a galaxy cluster, seen as a blob with a red through blue rainbow color map. The densest areas are in the center. 
Galaxy cluster CL 0016+16, z = 0.55, SZE σ=15µK, contours-30 μΚ (ΒΙΜΑ) X-ray false color (ROSAT PSPC).</a></label><br><a href="https://media.astrodon.social/media_attachments/files/113/853/196/100/860/133/original/fa5c9c2b25bbe8b8.png" rel="external">https://media.astrodon.social/media_attachments/files/113/853/196/100/860/133/original/fa5c9c2b25bbe8b8.png</a></li></ol></footer></blockquote>

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Kelly Lepo (kellylepo@astrodon.social)'s status on Tuesday, 21-Jan-2025 01:35:05 JST Kelly Lepo
in reply to
One early project was to look for the Sunyaev-Zeldovich (SZ) effect, caused when background light from the Cosmic Microwave background scatters off of the hot gas in galaxy clusters.
In conversationabout 4 months ago from astrodon.socialpermalink
Attachments
1. The Sunyaev-Zeldovich (SZ) effect Diagram shows a Microwave Background Photon entering Hot Cluster Gas. An Energetic Electron collides with the photon, producing a Blue Shifted Microwave Photon, obervied by a telescope. Photos of Sunyaev and Zeldovich, two friendly-looking middle-aged white men. One is in a leather jacket, tie and dress shirt. The other is in a suit. Two important tSZ points: 1) tSZ effect is a measure of total thermal energy, so good mass proxy. 2) Surface brightness of the SZ effect is independent of redshift! Sounds great, but the SZ effect is very low brightness and extended.
  https://media.astrodon.social/media_attachments/files/113/853/193/475/293/216/original/25a96b3017f83102.png
2. Worked like a charm • It worked very well. • Imaged hundreds of clusters selected from various X-ray catalogs. Built special purpose "Sunyaev-Zel'dovich Array," eventually integrated into CARMA. • Science results included initial SZ mass scalings, pressure profiles, constraints on the matter density parameter Ω™ and the Hubble constant Ho. • But needed more sensitivity (faster mapping speed) to discover galaxy clusters in cosmological surveys (more on that later). • Motivated using interferometry to measure intrinsic cosmic microwave background (CMB) anisotropy. Image of a galaxy cluster, seen as a blob with a red through blue rainbow color map. The densest areas are in the center. Galaxy cluster CL 0016+16, z = 0.55, SZE σ=15µK, contours-30 μΚ (ΒΙΜΑ) X-ray false color (ROSAT PSPC).
  https://media.astrodon.social/media_attachments/files/113/853/196/100/860/133/original/fa5c9c2b25bbe8b8.png

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