{"id":32665,"date":"2022-06-16T00:00:00","date_gmt":"2022-06-16T00:00:00","guid":{"rendered":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/?post_type=purple_issue&p=32665"},"modified":"2022-07-12T14:57:06","modified_gmt":"2022-07-12T14:57:06","slug":"listening-in-to-black-hole-echoes","status":"publish","type":"post","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/2022\/06\/16\/listening-in-to-black-hole-echoes\/","title":{"rendered":"Listening in to black hole echoes"},"content":{"rendered":"\n

Bouncing X-rays could help reveal the hidden landscape surrounding black holes<\/p>\n\n

\"\"
It\u2019s not the black hole itself that echoes, but the gas that surrounds it, illuminated by energetic X-rays <\/figcaption><\/figure><\/div>\n\n

As the team <\/strong>behind the recent image of the Milky Way\u2019s heart know only too well, investigating black holes is incredibly difficult because they are exactly that \u2013 black. The Event Horizon Telescope team managed it using a planet-sized telescope, but in the meantime, another team has been using a more unusual method \u2013 echolocation. <\/p>\n\n

The Milky Way is home to tens of millions of black holes, left behind by supernovae. Most of the time they are invisible until they feast on the gas around them, creating a burst of X-rays. This then bounces and echoes off the surrounding gas, illuminating it. Now a team of astronomers from MIT has tracked down a total of 10 echoing black holes \u2013 eight of which were new discoveries \u2013 and watched them for several months. <\/p>\n\n

\u201cThese black holes range in mass from five to 15 times the mass of the Sun, and they\u2019re all in binary systems with normal, low-mass, Sun-like stars,\u201d says Jingyi Wang from MIT, who led the study. <\/p>\n\n

By comparing the delay in light from the black hole\u2019s corona arriving at Earth to the arrival of echo, the team was able to create a map of gas around the black hole. <\/p>\n\n

This revealed that the black holes initially go through a \u2018hard\u2019 stage, lasting a few weeks, where they form coronas of high-energy photons and shoot out jets of material at near light speeds. The jets and corona first begin to sputter, before transitioning back to a low-energy \u2018soft\u2019 phase. The team saw that as the black hole transitioned from hard to soft, the time lag of the echo increased, suggesting the gap between the corona and the surrounding disc was growing larger. <\/p>\n\n

One explanation is that the corona experiences a brief expansion outwards as it finishes its cosmic feast, then retracts. <\/p>\n\n

\u201cWe\u2019re at the beginnings of being able to use these light echoes to reconstruct the environments closest to the black hole,\u201d says Erin Kara from MIT. \u201cNow we\u2019ve shown these echoes are commonly observed, and we\u2019re able to probe connections between a black hole\u2019s disc, jet and corona in a new way.\u201d <\/p>\n\n

<\/p>\n\n

ILLUSTRATION: AURORE SIMONNET AND NASA\u2019S GODDARD SPACE FLIGHT CENTER, SPITZER: NASA\/JPL-CALTECH; MIRI: NASA\/ESA\/CSA\/STSCI, UNIVERSITY OF CANTERBURY, HEATHER ROPER <\/p>\n","protected":false},"excerpt":{"rendered":"

Bouncing X-rays could help reveal the hidden landscape surrounding black holes<\/p>\n","protected":false},"author":24,"featured_media":33001,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"ub_ctt_via":"","purple_page_number":"12","purple_custom_meta_purple_page_number":"12","purple_seq_number":"1","purple_custom_meta_purple_seq_number":"1","purple_source_article":"article_12-1.xml","purple_custom_meta_purple_source_article":"article_12-1.xml","purple_source_issue":"July-2022","purple_custom_meta_purple_source_issue":"July-2022","purple_external_id":"July-2022-12-1","purple_custom_meta_purple_external_id":"July-2022-12-1","purple_issue_code":"|0000086554||","purple_custom_meta_purple_issue_code":"|0000086554||","purple_android_product":"com.im.skyatnight.206","purple_custom_meta_purple_android_product":"2022skyatnightJuly","purple_ios_product":"com.im.skyatnight.206","purple_custom_meta_purple_ios_product":"2022skyatnightJuly","purple_web_product":"","purple_custom_meta_purple_web_product":"","purple_publication_id":"075fab74-0a21-4201-866a-899d6c41c40c","purple_migrated":"","kt_blocks_editor_width":""},"categories":[19],"tags":[14],"featured_image_src":"https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/06\/MIT-BlackHoleEcho-01-press_preview.jpg","author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"acf":{"readingTimeMinutes":"2","apple_news_title":""},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/06\/MIT-BlackHoleEcho-01-press_preview.jpg",1600,1068,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/06\/MIT-BlackHoleEcho-01-press_preview-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/06\/MIT-BlackHoleEcho-01-press_preview-300x200.jpg",300,200,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/06\/MIT-BlackHoleEcho-01-press_preview-768x513.jpg",768,513,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/06\/MIT-BlackHoleEcho-01-press_preview-1024x684.jpg",800,534,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/06\/MIT-BlackHoleEcho-01-press_preview-1536x1025.jpg",1536,1025,true],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/06\/MIT-BlackHoleEcho-01-press_preview.jpg",1600,1068,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"Bouncing X-rays could help reveal the hidden landscape surrounding black holes","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/32665"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"replies":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/comments?post=32665"}],"version-history":[{"count":4,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/32665\/revisions"}],"predecessor-version":[{"id":33329,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/32665\/revisions\/33329"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/33001"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=32665"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=32665"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/tags?post=32665"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}