Image of the Week

Gaia's view of open clusters: a case study of R136 in the Large Magellanic Cloud

 

Gaia will observe thousands of open clusters in the galactic disk but will also reach clusters in the Magellanic Clouds. This image - courtesy Jos de Bruijne and Guido De Marchi (Research and Scientific Support Department of the European Space Agency) - presents a case study of the massive cluster R136, the central ionising star cluster of the Tarantula nebula (30 Doradus) in the Large Magellanic Cloud. Through simulations using the on-board object-detection software in combination with a cluster membership list based on deep HST images, it is found that, even in this massively dense and crowded environment, Gaia is capable of detecting stars down to 20-th magnitude. The main sequence of the cluster, as well as the field-star red clump, are representatively sampled.

The image, representing an astrometric AF2 CCD of the R136 cluster and surroundings, has been generated using the Gaia Instrument and Basic Image Simulator (GIBIS, developed within the Gaia Data Processing and Analysis Consortium – DPAC) based on a user-supplied source list. The default GIBIS configuration has been used, with typical cosmic-ray rates, sky background, CCD noise, etc., but Gaia's secondary telescope – which is normally superimposed at focal-plane level – has been blinded and charge injection has been disabled to ease the interpretation of the simulation. The source list is based on HST WFC3/UVIS images (6848 seconds in F555W ~ V and 10,656 seconds in F814W ~ I, 39 mas pixel-1, 162'' × 162'') taken on 20 October 2009 as part of the WFC3 Early-Release Science (ERS) programme (HST proposal 11360 by O'Connell et al.). The source list extracted from these images extends beyond V = 25 mag and contains 22,081 stars (De Marchi et al., 2011, ApJ, submitted). The associated object density is 11 million stars deg-2. The density of stars with G < 20 mag – which is the Gaia faint limit for astrometry and photometry – is 1.4 million objects deg-2. The source list has been extended with a representative background sample of stars to cover an area equal to the Gaia CCD height (1966 across-scan pixels, or 350'') and spanning 4.0 seconds of Gaia scanning time (4096 along-scan pixels, or 240'', or ~60 pc in linear dimension at the distance of the Large Magellanic Cloud). The extended source list contains 69,166 stars. Feeding this source list to GIBIS, 11,742 sources have been generated, all with G < 22 mag. The green boxes indicate observation windows allocated by the on-board software.

More details are available in this poster and the associated legend. A higher resolution poster is available here (17.8M).

This work has made extensive use of the Gaia Instrument and Basic Image Simulator (GIBIS), developed by Carine Babusiaux (Observatoire de Paris-Meudon, France) and collaborators within Coordination Unit 2 (CU2) of the Gaia Data Processing and Analysis Consortium (DPAC) and deployed by the Centre National d'Études Spatiales (CNES, Toulouse, France), as well as of the Gaia Video Processing Algorithms (VPA) prototype, developed by EADS Astrium SAS (Toulouse, France). Carmen Blasco (Research and Scientific Support Department, ESA) kindly provided support with running GIBIS and interpreting the results.

Image: Jos de Bruijne and Guido De Marchi

[Published: 22/06/2011]

 

Image of the Week Archive

2017
24/11: Gaia-GOSA service
27/10: German Gaia stamp in the making
19/10: Hertzsprung-russell diagram using Gaia DR1
05/10: Updated prediction to the Triton occultation campaign
31/08: Close stellar encounters from the first Gaia data release
16/08: Preliminary view of the Gaia sky in colour
07/07: Chariklo stellar occultation follow-up
24/04: Gaia reveals the composition of asteroids
20/04: Extra-galactic observations with Gaia
10/04: How faint are the faintest Gaia stars?
24/03: Pulsating stars to study Galactic structures
09/02: Known exoplanetary transits in Gaia data
31/01: Successful second DPAC Consortium Meeting
2016
23/12: Interactive and statistical visualisation of Gaia DR1 with vaex
16/12: Standard uncertainties for the photometric data (in GDR1)
25/11: Signature of the rotation of the galactic bar uncovered
15/11: Successful first DR1 Workshop
27/10: Microlensing Follow-Up
21/10: Asteroid Occultation
16/09: First DR1 results
14/09: Pluto Stellar Occultation
15/06: Happy Birthday, DPAC!
10/06: 1000th run of the Initial Data Treatment system
04/05: Complementing Gaia observations of the densest sky regions
22/04: A window to Gaia - the focal plane
05/04: Hipparcos interactive data access tool
24/03: Gaia spots a sunspot
29/02: Gaia sees exploding stars next door
11/02: A new heart for the Gaia Object Generator
04/02: Searching for solar siblings with Gaia
28/01: Globular cluster colour-magnitude diagrams
21/01: Gaia resolving power estimated with Pluto and Charon
12/01: 100th First-Look Weekly Report
06/01: Gaia intersects a Perseid meteoroid
2015
18/12: Tales of two clusters retold by Gaia
11/11: Lunar transit temperature plots
06/11: Gaia's sensors scan a lunar transit
03/11: Celebrity comet spotted among Gaia's stars
09/10: The SB2 stars as seen by Gaia's RVS
02/10: The colour of Gaia's eyes
24/09: Estimating distances from parallaxes
18/09: Gaia orbit reconstruction
31/07: Asteroids all around
17/07: Gaia satellite and amateur astronomers spot one in a billion star
03/07: Counting stars with Gaia
01/07: Avionics Model test bench arrives at ESOC
28/05: Short period/faint magnitude Cepheids in the Large Magellanic Cloud
19/05: Visualising Gaia Photometric Science Alerts
09/04: Gaia honours Einstein by observing his cross
02/04: 1 April - First Look Scientists play practical joke
05/03: RR Lyrae stars in the Large Magellanic Cloud as seen by Gaia
26/02: First Gaia BP/RP deblended spectra
19/02: 13 months of GBOT Gaia observations
12/02: Added Value Interface Portal for Gaia
04/02: Gaia's potential for the discovery of circumbinary planets
26/01: DIBs in three hot stars as seen by Gaia's RVS
15/01: The Tycho-Gaia Astrometric Solution
06/01: Close encounters of the stellar kind
2014
12/12: Gaia detects microlensing event
05/12: Cat's Eye Nebula as seen by Gaia
01/12: BFOSC observation of Gaia at L2
24/11: Gaia spectra of six stars
13/11: Omega Centauri as seen by Gaia
02/10: RVS Data Processing
12/09: Gaia discovers first supernova
04/08: Gaia flag arrives at ESAC
29/07: Gaia handover
15/07: Eclipsing binaries
03/07: Asteroids at the "photo finish"
19/06: Calibration image III - Messier 51
05/06: First Gaia BP/RP and RVS spectra
02/06: Sky coverage of Gaia during commissioning
03/04: Gaia source detection
21/02: Sky-background false detections in the sky mapper
14/02: Gaia calibration images II
06/02: Gaia calibration image I
28/01: Gaia telescope light path
17/01: First star shines for Gaia
14/01: Radiation Campaign #4
06/01: Asteroid detection by Gaia
2013
17/12: Gaia in the gantry
12/12: The sky in G magnitude
05/12: Pre-launch release of spectrophotometric standard stars
28/11: From one to one billion pixels
21/11: The Hipparcos all-sky map
15/10: Gaia Sunshield Deployment Test
08/10: Initial Gaia Source List
17/09: CU1 Operations Workshop
11/09: Apsis
26/08: Gaia arrival in French Guiana
20/08: Gaia cartoons
11/07: Model Soyuz Fregat video
01/07: Acoustic Testing
21/06: SOVT
03/06: CU4 meeting #15
04/04: DPCC (CNES) 
26/03: Gaia artist impression 
11/02: Gaia payload testing  
04/01: Space flyby with Gaia-like data
2012
10/12: DPAC OR#2. Testing with Planck
05/11: Galaxy detection with Gaia
09/10: Plot of part of the GUMS-10 catalogue
23/07: "Gaia" meets at Gaia
29/06: The Sky as seen by Gaia
31/05: Panorama of BAM clean room
29/03: GREAT school results
12/03: Scanning-law movie
21/02: Astrometric microlensing and Gaia
03/02: BAM with PMTS
12/01: FPA with all the CCDs and WFSs
2011
14/12: Deployable sunshield
10/11: Earth Trojan search
21/10: First Soyuz liftoff from the French Guiana
20/09: Fast 2D image reconstruction algorithm
05/09: RVS OMA
10/08: 3D distribution of the Gaia catalogue
13/07: Dynamical Attitude Model
22/06: Gaia's view of open clusters
27/05: Accuracy of the stellar transverse velocity
13/05: Vibration test of BAM mirrors
18/04: L. Lindegren, Dr. Honoris Causa of the Observatory of Paris
19/01: Detectability of stars close to Jupiter
05/01: Delivery of the WFS flight models
2010
21/12: The 100th member of CU3
17/11: Nano-JASMINE and AGIS
27/10: Eclipsing binary light curves fitted with DPAC code
13/10: Gaia broad band photometry
28/09: Measuring stellar parameters and interstellar extinction
14/09: M1 mirror
 
Please note: Entries from the period 2003-2010 are available in this PDF document.