SKA launches data chal­lenge

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THE SQUARE Kilo­me­tre Ar­ray Or­gan­i­sa­tion (SKAO) has re­leased its first ever Science Data Chal­lenge, giv­ing astronomers a taste of the highly de­tailed im­ages that the SKA tele­scope, to be si­t­u­ated in a re­mote area of the North­ern Cape, will pro­duce.

De­vel­oped by the SKAO’s Pro­ject Science team, the chal­lenge re­quires the anal­y­sis of a se­ries of high res­o­lu­tion im­ages cre­ated through data sim­u­la­tions. Re­searchers are in­vited to down­load the im­ages and use their own soft­ware to find, iden­tify and clas­sify the sources.

The key aim of the se­ries of Data Chal­lenges is to pre­pare the science com­mu­nity for the kind of data prod­ucts they will re­ceive from SKA ob­ser­va­tions and to gather valu­able feed­back which will in­form the de­vel­op­ment of data re­duc­tion pro­ce­dures.

“We’re test­ing meth­ods to ef­fi­ciently and ac­cu­rately dis­cover and clas­sify ob­jects. SKA im­ages will be crowded with sources, so this process has to be au­to­mated,” SKA science direc­tor, Dr Robert Braun, said.

“We want to know what astronomers can de­duce from these im­ages, and what it is that has led them to those con­clu­sions. We’re also ea­ger for the wider astron­omy and physics com­mu­nity to get in­volved in the chal­lenge, be­yond the ra­dio com­mu­nity, so that we can share in their ex­per­tise and ideas,” Braun added.

The first Science Data Chal­lenge con­sists of nine large im­ages, each be­ing about 32 000 pix­els on each side and 4GB in size. They show how the SKA’s mid-fre­quency ar­ray, to be lo­cated in the North­ern Cape, would see the ra­dio sky at three dif­fer­ent fre­quen­cies (560 MHz, 1.4 GHz and 9.2 GHz), and at three depths: eight hours, 100 hours and 1 000 hours of ob­serv­ing time.

A longer ob­ser­va­tion al­lows astronomers to see deeper into the uni­verse, re­veal­ing more ob­jects within the field of view. Fu­ture Science Data Chal­lenges will also sim­u­late datasets for the SKA’s low-fre­quency tele­scope, which will be sited in Aus­tralia.

“This is an ex­cep­tion­ally de­tailed rep­re­sen­ta­tion of the sky of­fer­ing a wealth of in­for­ma­tion for astronomers,” SKA pro­ject sci­en­tist, Dr Anna Bonaldi, who has been lead­ing de­vel­op­ment of the data chal­lenge, said.

“We are ex­cited to see what our col­leagues are able to draw from this, and from our fu­ture chal­lenges which will be­come pro­gres­sively more so­phis­ti­cated over the next few years. At 4GB each, these im­ages are al­ready com­plex but they’re just a frac­tion of the size of a full SKA im­age, so we can think of this as a ‘warm-up’, to get peo­ple ready for much big­ger things,” she added.

To cre­ate the im­ages, Bonaldi used a sta­tis­ti­cal model for the kinds of sources that oc­cur through­out the uni­verse, based on the most re­cent sky sur­veys car­ried out at many dif­fer­ent fre­quen­cies. This al­lowed her to pre­dict what the SKA, as a hugely sen­si­tive tele­scope, would be able to see.

Re­sponses to this first Data Chal­lenge that are sub­mit­ted by March 15 2019 will be eval­u­ated and pre­sented at the SKA Science Con­fer­ence the fol­low­ing month.

RES­O­LU­TION: SKA Or­gan­i­sa­tion

A snap­shot from the SKA Science Data Chal­lenge im­age, show­ing a large Ac­tive Ga­lac­tic Nu­cleus (AGN) as if ob­served by SKA-mid at 1.4 GHz.

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