Space-based Observational Astronomy

Prof. Dr. Şölen Balman

METU

◗ Astronomy & Astrophysics is the study of space outside our atmosphere.

◗ What can we see when we look at the sky on a clear night ?

Twinkle Twinkle little star ?….Planets….. Satellites!!…comets...meteor showers…..

◗ Where are we located ?Where are we located ? Earth !!!Earth !!! Solar SystemSolar System

Milkyway GalaxyMilkyway Galaxy

Local GroupLocal Group

Local Super Cluster Local Super Cluster

Great Attractor (Wall)Great Attractor (Wall)

UniverseUniverse

How Do We View the Sky ?

The Solar System --- FormationThe Solar System --- Formation

Size = 80 A.U. 1 A.U.=1.5x1013 cm

MILKY WAY GALAXY ---- SIDE VIEW

1 pc = 3.09x1018 cm ≃ 3.26 ly ---- 1kpc = 1000 pc

1 ly = c t = 3x1010 cm/s 3x107 sec = 9x1017 cm

GALAXY FORMATIONGALAXY FORMATION

View of our Galaxy as we View of our Galaxy as we observe it through Telescopesobserve it through Telescopes

LOFAR is the largest connected radio telescope ever built,using a new concept based on a vast array of omni-directional antennas. The project is based on an interferometric array of radio telescopes using about 25,000 small antennas concentrated in at least 48 larger stations. 40 of these stations are distributed across the Netherlands, five stations in Germany, and one each in Great Britain, France and Sweden. The total effective collecting area is up to approximately 300,000 square me meter.

408 Mhz

THE LOCAL GROUP ---- 20-30 galaxies

THE LOCAL SUPER CLUSTERTHE LOCAL SUPER CLUSTER

------ 200 Million LY IN SIZE

HOSTS OVER A MILLION

GALAXY

CLUSTERS

2 Micron All-Sky Redshift Survey

This survey aims to map the distribution of galaxies and dark matter in the local universe, out to a mean redshift of z = 0.03 (roughly equivalent to 115 Mpc or 370 million light-years). Out to a Limiting magnitude of K=11.8 is used and 45000 galaxies is displayed. Red are the farthest objects with redshift around 0.07 and blue toviolet are the lowest reshift objects that are closest.

Visiable Universe out to 600 Mpc

OUR VISOR OF THE UNIVERSE : TELESCOPES

Why do we need Telescopes ?◗ Large collection area◗ long integration time◗ Magnification◗ Resolution --- Θ = λ / D

Transmission of the Atmosphere --- Why do we need telescopes in space ?

REFLECTORSREFLECTORS

REFRACTORSREFRACTORS

AND AND

DIFFERENTDIFFERENT

WAVELENGTHWAVELENGTH

CONFIGURATIONSCONFIGURATIONS

ARECIBOARECIBO -- 300m300m

Radio wavelengthsRadio wavelengths

3.5 m -- CTIO Chile3.5 m -- CTIO Chile

optical wavelengthsoptical wavelengths

Very Large Array, New Mexico USA

TWIN KECK TelescopesMulti-mirror telescopeMount Kea Hawaii10 m each mirror with 36 segments of 1.8m mirrors

AUXILLIARY INSTRUMENTS◗ Guiding Systems◗ Cameras◗ Cooling Systems◗ Spectrographs (gratings that disperse light in

wavelength)◗ Detectors

Charge Coupled Devices (CCD)

Scintillation Counters

Proportional Counter Arrays

Multi-Channel Plates

OBSERVATORIES IN SPACE

◗ Microwave : COBE -- WMAP ◗ Infra Red : IRAS, ISO – SPITZER,

Planck, Herschel◗ Optical : HST◗ Ultra Violet : IUE, EUVE – FUSE, GALEX◗ X-Ray : ROSAT, ASCA, Beppo-Sax--

RXTE, Chandra, Suzaku, XMM-Newton◗ Gamma-Ray : GRO -- INTEGRAL, SWIFT,

Fermi, AGILE

CHANDRA OBSERVATORY 0.1 -- 10 keV

July 199910mx1.2m4790 kg133000 km-16000 km64.2 hours

CHANDRA CHANDRA SCIENCE: DATA SCIENCE: DATA AND SPECTRAAND SPECTRA

Chandra X-Ray Observatory -- 0.1-10 keV

Crab Nebula CAS A

Galactic Plane

Chandra X-Ray Observatory

CXChttp://chandra.harvard.edu

HUBBLE SPACE TELESCOPEHUBBLE SPACE TELESCOPE

April 1990 - today

2.4 m mirror size

0.05 arcsec resolution

11110 kg – 559 km

97 minutes

HST STIS DATA AND SPECTRAHST STIS DATA AND SPECTRA

HST HERITAGEHST HERITAGE

MULTIWAVELENGTH STUDIES MULTIWAVELENGTH STUDIES