France and China have launched a satellite to explore the universe's first stars

In a few days, China will launch the SFOM space mission (Multi-Scale Astronomical Variable Object Observer)Fruit of French-Chinese cooperation (*)) Dedicated to the study of gamma-ray bursts, these fascinating astronomical phenomena resulting from the explosions of more distant stars. Svom will be launched on June 22, 2024 from Xichang Cosmodrome, aboard a Long March 2C launcher. Its mission is scheduled to last three years, with the possibility of extending it for an additional three years.

A window into the early universe

The goal of this mission is to explore gamma bursts in depth LightningLightning from U.S brightnessbrightness Exceptional, among the oldest and most remote recorded events in the world UniverseUniverse. This light was sometimes emitted when the universe was less than a billion years old, or 5 to 10 percent of its current age. By investigating these ephemeral cosmic phenomena, SFOMM opens the door to research doordoor from U.S WindowWindow A timeline that allows us to delve into the primordial universe, explore its first stars, and analyze the stellar environment of these distant eras.

Understanding the formation of the universe over time

Before reaching us, the light from these gamma-ray bursts passes through many billionsLight yearLight yearThus encrypting important information about the history and development of the universe. Thus, these indicators can give us clues about the elemental content of the universe, the composition among stars, and even the dynamics of the universe. GasGas Galaxy as well as information about GalaxiesGalaxies The hosts of these explosions.

The phenomena are very difficult to observe due to the short duration of gamma ray emission

However, studying gamma-ray bursts remains a major challenge due to their brevity DurationDuration toemissionemissionThey range from fractions of a second to just a few tens of seconds. To meet this challenge, the Svom mission relies on an arsenal of four advanced instruments, designed to detect, locate and study them with great precision and responsiveness. So we calculate telescopetelescope ECLAIRs, for detecting and locating gamma bursts in a range X rayX ray And the Gamma raysGamma rays Deep voice energyenergyMXT telescope for observing gamma bursts in the soft X-ray field SpectrometerSpectrometer Wide range GRM gamma which will measure DomainDomain At high energy gamma ray bursts in addition to a telescope operating in the visible and very near range InfraredInfraredwhich will detect and monitor the light emission produced immediately after the gamma ray burst.

The short duration of gamma-ray bursts required a very complex strategy devised for the Svom mission in order to collect data while avoiding downtime. For this reason, the instruments are simply technological gems and the ECLAIRs telescope uses one of these instruments ProgrammingProgramming The most complex space instrument ever used required six years of development at CEA.

Finally, due to its unparalleled interactivity and robotic instruments, Svom can be used to observe transient cosmic phenomena, that is, objects that are ephemeral or whose luminosity changes over time, such as supernovas or gravitational wave sources.

*The mission is the result of cooperation between the two national space agencies CNSA (China National Space Administration) The CNES (National Center for Space Studies) with major contributions from CEA, the French National Center for Scientific Research in France and the National Astronomical Observatory (NowNow) and institute physicalphysical Beijing Higher Energy Institute (IHEP) in China.

France and China set out to search for gamma rays using a space telescope

Article from Daniel ChretienDaniel Chretienpublished on 03/08/2023

Svom's Franco-Chinese mission is progressing well. The French machines are ready to leave to be integrated into the smaller machines Space telescopeSpace telescope Chinese. It is scheduled to take off in December.

sfum (Monitoring multi-scale astronomical variable objects in space) aims to capture gamma ray bursts, an extreme event that is among the most extreme known in the world AstrophysicsAstrophysics. These are signatures, in form BlinksBlinksGiant explosions. They are considered the brightest and richest elements since the Big Bang. The released energy corresponds to more than a thousand billion SunsSuns !

Rare events

At best, we can observe about ten per day. They are so bright that we can observe them beyond the boundaries of our galaxy. But they are very difficult to detect because these bursts are random and unpredictable. They can come from SupernovaeSupernovae Or shocks between huge objects, such as black holesblack holes Or some Neutron starsNeutron stars.

Gamma burst animation. © NASA

To detect the gamma burst, Svom is equipped with a screena screen It consists of three detectors to cover a large portion of the sky. Each is placed in a different direction, so you can pinpoint the location of the explosion. The information from this detector can complement that of Gravitational wavesGravitational waves From Earth (using Ligo and Virgo tools).

Once detected, the explosion is monitored with three different telescopes. Two of them are provided under French project management: ECLAIRs (developed at the Institute of Research in Astrophysics and Planetology in Toulouse in partnership with CEA and the University of Paris-Saclay), and MXT (CEA with British and German participation). ECLAIRs detect in X-rays and soft gamma rays, and MXT detects in X-rays in a narrower field of view. Finally, the Visible Light Telescope (VT) will observe the light produced immediately after the explosion.

French-Chinese cooperation

CNES and the Chinese Space Agency have already cooperated on other missions. The one on Svom dates back to 2014. Cnes supplies the main telescopes, the ECLAIRs and MXT, while China supplies the other telescope, display and platform for the 930-kilo space telescope. a rocketrocket The Long March 2C will put it in its place It rotates in orbitIt rotates in orbit Low ground.

Svom, the future gamma blast hunter, receives his sensors

Article from Remy DecorRemy Decorpublished on November 14, 2010.

A small satellite dedicated to studying gamma-ray bursts, SFOM It is scheduled to be launched in 2015. You will receive it soon SensorsSensors Dedicated prototypes for the Eclairs telescope, the satellite's main payload.

The result of cooperation between France and China, the Svom satellite (Space-based multi-scale variable object observer) About the platform ProteusProteus From the central nervous system. Its development continues with the delivery of prototype sensors.

Made by department Safran Electronics from Sagem In his institution ParityParityThese sensors detect X and gamma radiation, and each includes 32 telluride detectors CadmiumCadmium (KD T). They will prepare the telescope Lightninga wide-field instrument operating in the range from 4 to 300 keV that will provide real-time gamma-ray burst locations with an accuracy of less than 10 Minute of arcMinute of arc. All of these detectors will form a sensor with a useful surface area of ​​1000 cm².

Events associated with the formation of black holes

sfum It will be launched in 2015 at an altitude of 625 km and will operate for 3 years with the possibility of extending its mission for another 3 years. It will monitor more than 200 gamma-ray bursts, and will help us better understand their nature and the formation of the first objects in the universe. After l the great explosionthe great explosionThese explosions are among the most violent astrophysical phenomena known in the universe. They appear through intense, variable and short emissions of X-rays and gamma rays: they last only from a few milliseconds to a few hours. If they remain mysterious for a long time, then… AstrophysicistsAstrophysicists Today connect them withCollapsesCollapses A massive star in rapid rotation or… CoalitionCoalition two starsstars Compact (neutron stars or black holes).

SFOM owns 4 high-energy visible and infrared telescopes, manufactured by China and France. Another important device, the radio system Ultra high frequencyUltra high frequency Which will be responsible for quickly providing the location of observed explosions to the entire scientific community, within a few minutes.

To properly monitor gamma-ray bursts, which last for a very short time, it is actually necessary to monitor them over a wide range of… WavelengthsWavelengths And throughout their entire lives. It is therefore necessary to continue the study begun on board the satellite through observations on Earth using larger and more efficient telescopes.