Transcript Mon titre - indico in2p3

Bibliotheque du LUPM
• Localisation et Evolution temporelle
• Personnel
• Journaux et abonnements
• Livres
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Localisation
Au 4ieme etage (livres + presentoir)
Au sous –sol (vieux livres …)
Dans les bureaux
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Evolution temporelle
Futur: espoir de stabilisation
• Ameliorations necessaires: signaletique;
rangement des livres; livres manquants, etc
• ½ journee consacree/an: reunion utilis. + pot
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Personnel
Actuellement:
Dahbia pour les abonnements
Moi-meme (livres + revues)
Dans le futur :
• une ou un bibliothecaire a demander (1/2 ?)
• A defaut: Dahbia + Nicolas + Matthieu R.
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Revues et Magazines:
Physics Today; Science; La Recherche; Pour la
Science; Sky and Telescope; Ciel et espace;
Decouverte
Linux Magaz.; Mesures; Elektor electronique
Open Silicium
Sur le presentoir ou chez les
specialistes
Sur les etageres
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Journaux scientifiques acces
electroniques
• Astrophysical Journal
• Astronomical Journal
• Astronomy et Astrophysics
• Budget Journaux + Magazines 7600 euros
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Livres
• Budget livres 2000 euros soit environ 40 achetes/an ; les
besoins en ouvrages sont satisfaits en tres grande majorite
• La place va manquer, mais on peut eliminer (bien que difficile)
= Mieux vaut un livre qui sert a quelqu’un dans son bureau que
inerte dans la bibliotheque
Le fichier des livres est enfin accessible a tous
Tracabilite importante (cahier+ liste des emprunts diffusee)
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Quelques stats sur le fichier des livres
1500 livres au total; 500 edites apres l’an 2000
510 Math : 40 livres;
530 Physique : 117 livres;
52.48 Htes energies: 20 livres
Livres “perso” des gens acceptant de les preter: 100
Livres actuellement empruntes: environ 100
Livres acquis par an: 40-50 ; temps de doublem. 30 ans
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CONCLUSIONS
Les suggestions sont les bienvenues
½ Journee des utilisat. entre Septembre et Noel
Dahbia et moi vous remercions pour votre attention (on a
essaye de faire au mieux)
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Astro-café 21 June 2013
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SUMMARY
INTRODUCTION : our GALAXY and the NEIGHBOURS
(small galactic satellites / globular clusters / streams/ isolated stars)
THE MASS OF THE GALAXY
SEARCH FOR CARBON STARS in the DISTANT HALO
CONCLUSIONS
DRINK: BLANQUETTE DE LIMOUX and cakes
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Barred Spiral Galaxy, NGC 6217 which
ressembles the Milky Way
( bulge,bar,disk,arms, large halo unseen here)
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An example of Tidal streams in isolated spirals
(Martinez-Delgado 2010)
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Globular cluster Omega Centauri
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Luminosity color diagram
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Another luminosity vs color diagram
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Globular cluster Palomar 5
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Disrupted globular cluster Palomar 5
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Large Magellanic Cloud; the nearest “external”
galaxy (bound or unbound ?)
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Obtaining the mass of the Galaxy with distances
and velocities
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masse m orbitant autour de masse M
On suppose orbite circulaire
force centrifuge = force d attraction gravitat.
m V**2 / R = G m M / R**2
m vanishes; and M = 1/G R V**2
(magic …)
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Balance of Cavendish (drawing
and rebuilt by Georges Paturel);
with this device, you measure G
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Balance of Cavendish (G. Paturel)
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Measuring the Mass of the Galaxy
(it’s “Dark Matter” mainly)
• Find an object (small galaxy) orbiting the
Galaxy
• Measure R
(pc, or kpc, or light years)
• Measure V with respect to center (km/s)
• Calculate the product 1/G R V**2
• The greater R is, the better
• radial velocity ; tangential ?
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Trying the method with the Sun
Take Mercury, Venus, Earth, Mars … Pluto
• Compile distances to Sun in a book
• Estimate velocity in their orbit (2 pi R / Period)
• Calculate 1/G R * V**2
• It works: result= 2 10**33 grams +/- 1 percent
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(my guilty ignorance of Kepler’s law :
RV**2 ~ R R**2 /P**2 = a**3/P**2 =constant)
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What is the result for the Galaxy ?
Globular Clusters R up to ~ 100 kpc
Magellanic Clouds R ~ 50 kpc
Small orbiting satellite gal. (“dwarf galaxies”)
(Fornax R=130 kpc ; Leo I R = 230 kpc)
(desired: radial + tangential velocities)
Also wanted:
Isolated stars: BHB stars, carbon stars !
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The satellites of the Milky way
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Sculptor 87 kpc
Sextans 86 kpc
Carina 100 kpc
Draco 79 kpc
Fornax 138 kpc
Leo I 250 kpc
etc
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110 km/s +/-10 environ
226 km/s
+223 km/s
-223 km/s
+53 km/s
+287 km/s
RESULT
• Mass of the Galaxy (dark mainly)
• 0.5 to 2 10**12
solar masses
• Proper motions (needed to get V in 3D)
• An object may be bound or not
• The more there are “satellites”, the better
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Andromeda and its satellites
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Can the AGB carbon stars bring anything
interesting ?
TI98 218-5 d= 80 kpc +77 km/s
TI98 223 -13 d= 90 kpc +120
C star m54 d=130 kpc V=+2 km/s
C star m44 d= 55kpc v=-13
C star m45 d= 55 kpc v=+126
C star m11 d=66 kpc v= + 145
C star m12 d=65 kpc v= +85
C star m59 d=112 kpc v= ?
l=114.3 b=-61.35
Deason 136.44 +20 d=150 kpc v=+200 km/s
See Deason et al astro-ph 1205.6203
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AGB C stars in the halo. 34 were known in 1998
At K=11-12 they are at 50kpc from us
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Presently we know 134 C stars in the halo; some of
them at 130 kpc from us; can we find more of them ?
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A search for very distant C stars around the
Milky Way
• Start with the 2MASS catalog : photometry of
all sky at 1-2.5 mu
• |b|>20 degrees (Milky Way)
• K < 14.5 mag (to get reasonably good
photometry)
• J-K > 1.20 (to eliminate asmasp M dwarfs)
• Result: 765 000 candidates
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Galactic longitude-latitude map of the initial
2MASS objects
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Refining the cuts
• Good quality data + K > 7
• Location in JHK color-color diagram
• Elimination of LEDA galaxies
• Elimination of SDSS galaxies
• Elimination of Supercosmos galaxies
36835 objects survive
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lb map to be shown
Color Color diagrams with JHK
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36835 objects after removing at best the
galaxies
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Masking
LMC / SMC can be masked
Interstellar clouds with young stars as well
Survive 2056 objects
Examination of their light curves
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2056 candidates; 84 known C stars survived
Goal: other C stars to be identified
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Use of Catalina photometric monitoring database
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Have a look at the minimum mag
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Another example, with asymmetric light
curve
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This one is in Leo I at 230 kpc, unfortunately
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One irregular candidate so far;
spectroscopy needed
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CONCLUSIONS
• By studying the satellites of the Milky way (distances,
3D velocities), you measure its dark matter mass
• It is worth searching for distant carbon stars in the
halo, or distant stars of other types (BHB, RR Lyrae s,
bright giants, CH stars).
Most importantly, all this is of course a pretext
to have a drink after a few questions ….
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Merci beaucoup pour votre
attention
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