Astronomers at the University of Southampton are using X-ray vision to reveal supermassive black holes hidden beneath thick veils of interstellar gas in our cosmic neighbourhood.

Monster black holes sometimes lurk behind gas and dust, hiding from the gaze of most telescopes. But they give themselves away when material they feed on emits high-energy X-rays that NASA's NuSTAR (Nuclear Spectroscopic Telescope Array) mission can detect. That's how NuSTAR recently identified two gas-enshrouded supermassive black holes, located at the centres of nearby galaxies.

The findings of the work, led by Southampton-based PhD researcher Peter Boorman and Dr Poshak Gandhi, Associate Professor and STFC Ernest Rutherford Fellow in Southampton’s Astronomy Group, were presented during a press briefing at the 229th meeting of the American Astronomical Society in Grapevine, Texas, USA this month. Joining Peter Boorman at the press briefing was Ady Annuar, a graduate student at Durham University.

In a recent paper published in The Astrophysical Journal, Boorman (and colleagues from the NuSTAR active galaxies science team) described how data from NASA’s Nuclear Spectroscopic Telescope Array has been used to study the intrinsic behaviour of a ‘hidden’ supermassive black hole in a galaxy nearby to our own – IC 3639 – some 175 million light years from Earth, relatively close by in cosmic terms.

“Every large galaxy in the Universe is believed to host a supermassive black hole at their centre, millions of times the mass of our Sun,â€? says Boorman. “These systems can devour vast quantities of matter due to their extreme gravitational pull, making the black holes grow. The in-falling matter then emits radiation across the full electromagnetic spectrum. These growing supermassive black holes are called Active Galactic Nuclei (AGN).

“The emission can be absorbed by thick clouds of gas and dust covering the AGN,â€? Boorman continues. As the level of obscuration increases, only the highest energy X-rays can escape to be observed by us. X-rays are absorbed by the atmosphere so I use data from X-ray satellites located above our atmosphere – such as NuSTAR, Suzaku and Swift – to detect high energy X-ray emission throughout the Universe.â€?

“The black hole I’ve been studying is so hidden, that it requires highly sensitive observations in the highest energy X-rays to classify it as obscured. Such sensitivities are only available now with the NuSTAR satellite [launched in June 2012] which is designed to create images of the high energy X-ray sky sharper than ever before,â€? he adds. “By modelling the X-ray emission of supermassive black holes, we get a glimpse of their growth rates, and learn about the amount and composition of material blanketing them. IC 3639 turns out to be glowing extremely bright due to emission from hot Iron atoms whose origin is not fully understood.â€?

“In broader terms, we also hope to determine the distribution of obscured AGN across the Universe, and figure out how these supermassive black holes have evolved and grown over billions of years,â€? Boorman concludes. “For this purpose, we will soon begin a large new survey of other nearby AGN with NuSTAR, and we can expect many more discoveries in the coming years.â€?

Annuar's study of the spiral galaxy NGC 1448 discovered that X-ray emission from NGC 1448, as seen by NuSTAR and NASA’s Chandra X-Ray Observatory, suggests for the first time that, like IC 3639, there must be a thick layer of gas and dust hiding the active black hole in this galaxy from our line of sight.

Researchers also found that NGC 1448 has a large population of young (just 5 million year old) stars, suggesting that the galaxy produces new stars at the same time that its black hole feeds on gas and dust.

"These black holes are relatively close to the Milky Way, but they have remained hidden from us until now," said Annuar. "They're like monsters hiding under your bed."

Dr Gandhi believes that we are only now beginning to properly understand supermassive black hole growth in the obscured regime.

“Although X-ray astronomy was ‘born’ in the 1960’s, the field is still in its infancy in many respects,â€? he says. “NuSTAR is helping to change the picture of what we know about supermassive black holes, even in the local universe where many questions remain unanswered. It is really a privilege to be the first to peer into places in the universe where no one has been able to see before.â€?

Students at the University of Southampton already have an excellent record for their success in the jobs market, and with over 75 leading companies and organisations attending the 2017 Engineering and Technology Careers Fair, this looks set to continue.

This year's event takes place on Tuesday 14 February and welcomes for the first time companies such as Argos, Capgemini, Dyson, Ford, Meggitt, Toshiba, and Viagogo. They join regular attenders from global industry, such as Bloomberg, ARM, BAE Systems, CGI, IBM, Leonardo, JP Morgan, and PwC. The Fair is open to all students in the University and is one of the biggest Fairs on campus. This is the tenth Fair in the series and it continues to provide a great opportunity for leading tech companies to meet some of the UK's best students.

With 25 per cent of the companies attending for the first time and more companies than ever wanting to take part, there is no shortage of choice for students who are aiming to work in some of the UK’s leading and most innovative companies. The companies attending will be offering graduate jobs, summer internships and industrial placements, and aiming to build awareness of their opportunities with students who may not be entering the jobs market until 2019 or beyond. ‘This is a great opportunity for students to get a really wide-ranging view of the engineering and technology industry,’ said Joyce Lewis, Careers Fair Director, ‘as well as to find out about specific careers and opportunities in many different sectors.'

Sectors strongly represented this year include digital technology, finance, security, consultancy and innovative technology, and silicon systems. Innovative start-ups and specialized companies will also be represented, through the University's Science Park at Chilworth, and the Future Worlds incubator. The Fair's Innovation Zone highlights some of the leading technology being produced by companies based at Chilworth, who will be looking for the brightest students to join their high-tech ventures.

‘We very much welcome the high quality of companies coming to Southampton to employ our students', said Professor Bashir Al-Hashimi, Dean of Physical Sciences and Engineering. 'They are taking part in the Fair because they are aware of the quality of our students and their ability to innovate and support the development of future technologies. There are very exciting careers to be built in these industries and we value our strong links with companies and the excellent relationships built up over time. Many of the stands will include Southampton alumni, demonstrating the contribution that our students and graduates are making to the UK’s industrial and business success.’

Students attending the Fair can expect strong interest from leading employers across the technology industries and from companies that are seeking excellent graduates with high-level competence in technology and engineering, as well as business and the sciences.

‘The environment we have created here. based on our strong research reputation, continues to ensure that companies want to promote their opportunities to our students,' said Professor Al-Hashimi. 'For our part we do our best to increase our students’ awareness of career opportunities, right from their very first week at the University. We want to prepare them to find the job they want, and raise their aspirations of future achievement.’

For further information about the Fair, or about the FPSE Careers Hub activity, contact Joyce Lewis; tel.+44(0)23 8059 5453.

The University of Southampton is hosting a special ‘Stargazing Live’ event for all the family.

On Wednesday 11 January from 17:30 – 21:00, members of the public are invited to see the stars either from the comfort of the two Soton Astrodomes – the University’s inflatable mobile planetaria – or from the rooftop observatories.

This year also sees the launch of the University’s new Planeterrella, an incredible artificial demonstration of the Northern Lights.

The Astrodomes will be running planetarium shows during the evening and there will be a number of tours to view the stars and planets through the roof top telescopes. There will also be informal astrophotography workshops and talks from astronomy and space physics lecturers and academics on black holes, the Earth’s aurora and the life and death of stars.

The roof tours and planetarium shows are free but require tickets, which you can book by clicking here.

There are other free activities throughout the evening that do not require tickets. These include the hands-on activity ‘play doh planets’.

For those who can’t get a ticket for the roof observations, members of the Southampton Astronomical Society (SAS) and the South Coast Astronomy Group (SCAG) will also be outside at foyer level with their telescopes.

Dr Sadie Jones, Outreach Leader in Astronomy at the University said: "This free event provides a great opportunity to investigate our local night sky and encourages the public, young and old to discuss the big questions of the Universe with our astronomy academics."