Cut­ting-edge re­search led by Mal­tese as­tro­physi­cist sheds light on dis­tant uni­verse

The Malta Business Weekly - - FRONT PAGE -

Front-line re­search by a Mal­tese as­tro­physi­cist, who led a team of in­ter­na­tional as­tronomers, is shed­ding light on the dis­tant uni­verse and con­tribut­ing an­other piece to the com­plex cos­mic puz­zle.

“The story of the uni­verse is our own story. In a sense, as­tronomers are his­to­ri­ans. Our tele­scopes act as time ma­chines that al­low us to pore over light from the past. We then try to un­der­stand what this light is telling us and con­struct a time­line of how struc­ture evolved to be­come the gal­ax­ies we ob­serve to­day,” Univer­sity of Malta lec­turer Joseph Caru­ana said.

Dr Caru­ana’s re­search pa­per has just been ac­cepted for pub­li­ca­tion in the Monthly No­tices of the Royal Astro­nom­i­cal So­ci­ety, one of the world’s lead­ing, peer­re­viewed as­tron­omy jour­nals for the past 188 years.

The Pa­per presents the discovery of 100 gal­ax­ies that emit ul­tra­vi­o­let light known as Ly­man al­pha, a fea­ture in the spec­trum of light that acts as a “fin­ger­print” and en­ables as­tronomers to mea­sure the pre­cise dis­tance to th­ese gal­ax­ies.

When study­ing dis­tant gal­ax­ies, Ly­man al­pha is a much soughtafter fea­ture in the spec­trum of light. Gal­ax­ies that are form­ing new stars spew out Ly­man al­pha, so this fea­ture is a tracer of star for­ma­tion ac­tiv­ity in gal­ax­ies.

Dr Caru­ana, who forms part of the De­part­ment of Physics and the In­sti­tute of Space Sciences & As­tron­omy (ISSA), how­ever ex­plained that there were a num- ber of ob­sta­cles that hin­dered the emer­gence of this light and its es­cape is a key ques­tion in the study of gal­ax­ies.

More­over, the dis­tance to th­ese gal­ax­ies is so large that the uni­verse has ex­panded sig­nif­i­cantly in size since their light started the jour­ney to­wards Earth.

“We are look­ing into the deep past of our uni­verse, ob­serv­ing light that started its jour­ney be­tween 11.6 and 12.8 bil­lion years ago. Just imag­ine, the uni­verse is 13.8 bil­lion years old,” Dr Caru­ana added.

To carry out this study, the in­ter­na­tional team of as­tronomers, who are af­fil­i­ated to nine in­sti­tu­tions across Europe, used Muse, the Multi Unit Spec­tro­scopic Ex­plorer, a state-of-the-art in­stru­ment in­stalled on the Very Large Tele­scope in Chile. This in­stru­ment al­lows as­tronomers to ob­tain what is com­monly re­ferred to as a dat­acube, a data struc­ture that pro­vides a 3D view of the uni­verse.

“The story of our uni­verse is con­structed piece by piece, some­what akin to as­sem­bling a puz­zle, where as­tronomers strive to un­der­stand gal­ax­ies in their var­i­ous stages of for­ma­tion. Build­ing on years of work by the ded­i­cated com­mu­nity of the Muse con­sor­tium, this study rep­re­sents an ex­am­ple of what can be achieved with this sen­si­tive in­stru­ment in the study of dis­tant gal­ax­ies,” Dr Caru­ana said.

Roland Ba­con, the prin­ci­pal in­ves­ti­ga­tor of the Muse con­sor­tium from the Lyon Cen­tre for As­tro­physics Re­search com­mented that Muse is a unique in­stru­ment with in­com­pa­ra­ble per­for­mance, en­abling new sci­ence in many dif­fer­ent ar­eas of as­tro­physics: from the study of nearby galac­tic clus­ters to the most dis­tant gal­ax­ies.

“Muse is com­ple­men­tary to other, much more ex­pen­sive fa­cil­i­ties like the Hub­ble space tele­scope. This study im­proves our un­der­stand­ing of the dis­tant uni­verse and is a good ex­am­ple of what Muse al­lows in this com­pet­i­tive field,” Prof. Ba­con added.

The discovery of Dr Caru­ana’s team will be pre­sented at an in­ter­na­tional con­fer­ence be­ing held in Val­letta be­tween 2-6 Oc­to­ber. More than 100 as­tronomers from all over the world will con­verge in Malta to fo­cus on the topic of galac­tic dy­nam­ics. An event for the pub­lic will also be held on the evening of 5 Oc­to­ber at the Val­letta Cam­pus of the Univer­sity of Malta. More in­for­ma­tion can be found at http://gasin­galax­i­escon­fer­

The De­part­ment of Physics and the In­sti­tute of Space Sciences & As­tron­omy (ISSA) are also cur­rently in­volved in a num­ber of re­search projects, with stu­dents fo­cus­ing on prob­lems in var­i­ous fields, from ra­dio as­tron­omy to galac­tic dy­nam­ics, in­stru­men­ta­tion and night-sky bright­ness mea­sure­ments. In­ter­ested stu­dents can visit https:// www. um. edu. mt/ sci­ence/physics and for more in­for­ma­tion.

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