Tag: quasar

Hubble takes a different look at quasar 3C 273

10:25 am

Hubble's different views of 3C 273
Click for original image.

One of the most studied objects in the sky is the quasar 3C 273, located about 2.5 billion light years away and the first quasar ever to be identified, in 1963. What makes it especially interesting is the 300,000-light-year-long jet that shoots out from it.

Astronomers have now used the Hubble Space Telescope to take a different view of 3C 273, using the telescope’s coronograph to block the central bright light so that the surrounding dimmer features can be seen. The two images to the right, reduced and sharpened to post here, show what this new image (bottom) reveals when compared to an earlier Hubble image (top).

The new Hubble views of the environment around the quasar show a lot of “weird things,” according to Bin Ren of the Côte d’Azur Observatory and Université Côte d’Azur in Nice, France. “We’ve got a few blobs of different sizes, and a mysterious L-shaped filamentary structure. This is all within 16,000 light-years of the black hole.”

Some of the objects could be small satellite galaxies falling into the black hole, and so they could offer the materials that will accrete onto the central supermassive black hole, powering the bright lighthouse.

What makes this observation even more outstanding is that the image was produced by using Hubble’s Space Telescope Imaging Spectrograph (STIS) as the coronograph to block the bright center of 3C 273. This improvisation of STIS has been done many times before, but it remains a great example of clever thinking by the astronomers who use Hubble.

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Host galaxies for two quasars in early universe detected for the first time

10:06 am

Quasar and host galaxy
One of the quasars, with its light subtracted on the right,
revealing the host galaxy. Click for original image.

The uncertainty of science: Using data from both the infrared Webb Space Telescope and the Subaru optical telescope in Hawaii, astronomers have observed for the first time the host galaxies of two quasars that formed less than a billion years after the Big Bang.

Just a few months after JWST started regular operations, the team observed two quasars, HSC J2236+0032 and HSC J2255+0251, at redshifts 6.40 and 6.34 when the universe was approximately 860 million years old, both of which were discovered using Subaru Telescope’s deep survey program. The relatively low luminosities of these quasars made them prime targets for measuring the properties of their host galaxies.

The images of the two quasars were taken at infrared wavelengths of 3.56 and 1.50 microns with JWST’s NIRCam instrument, and the host galaxies became apparent after carefully modeling and subtracting glare from the accreting black holes. The stellar signature of the host galaxy was also seen in a spectrum taken by JWST’s NIRSPEC for J2236+0032, further supporting the detection of the host galaxy.

Photometric analyses found that these two quasar host galaxies are massive, measuring 130 and 34 billion times the mass of the Sun, respectively. Measuring the speed of the turbulent gas in the vicinity of the quasars from the NIRSPEC spectra suggests the black holes that power them are also massive, measuring 1.4 and 0.2 billion times the mass of the Sun. The ratio of the black hole to host galaxy mass is similar to those of galaxies in the more recent past, suggesting that the relationship between black holes and their hosts was already in place 860 million years after the Big Bang. [emphasis mine]

Normally, quasars are so bright the host galaxy is obscured. Computer modeling that subtracted the quasar’s light produced the host galaxy image on the right.

The highlighted sentence raises intriguing questions again about the Big Bang. Webb is once again finding evidence that the early universe quickly became like today’s universe, much faster than expected by cosmologists.

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