Science Drivers
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Science Drivers |
The FRIDA Project Instrument Overview Science Drivers IAC Contribution IAC Project Team Sky coverage with AO with natural or laser guide star Other NIR instruments IAC programs on high spatial resolution techniques and atmospheric optics Contact Database (internal) |
FRIDA's
scientific case is very broad: it ranges from solar system bodies to
high redshift systems, including close binary systems, young stellar
objects, circumstelar phenomena in advanced stages of stellar evolution
and active galactic nuclei. A number of scientific challenges for FRIDA are identified here:
High redshift at kpc scales with FRIDA
FRIDA and the nearest Universe FRIDA in our galaxy at sub-parsec scale High redshift at kpc scales with FRIDA
The challenge for AO-assisted instrumentation at high redshift is to get targets with a bright star next to it. The figure below shows examples of B-dropouts, from the HUDF, corresponding
to the redshift range 3.5 < z < 4.7 (Beckwith et
al. 2006, AJ 132) . Object sizes are typically less than 0.5 arcsec and thus FRIDA spatial scales are
ideal for their detailed spectroscopic study. Unfortunatly, these objects are difficult to
observe with AO instruments due to the lack of a relatively bright
star next to it. Thus, we call the attention of the GTC community on the planning of current or
future surveys, we encourage survey teams looking for
possibilities to explore fields with a relatively bright star, V< 16, in it so
that potential targets for follow up 2D spectroscopy with FRIDA become
possible!
Each image covers 1.9 x 1.9 arcsec^2 (13 x 13 kpc at z ~ 4). The FoV of FRIDA at its highest resolution mode is about half of that. The sizes of these objects are typically < 0.5 arcsec, thus FRIDA spatial scales are
ideal for their detailed spectroscopic study.
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| FWHM ~ 100 mas => | ~ 150 pc @ z=0.05 | |
| FWHM ~ 100 mas => | ~ 13 pc @ Virgo | => galaxies across the Hubble sequence |
| FWHM ~ 45 mas => | ~ 0.7 pc @ M82 | => the nearest starburst |
| FWHM ~ 45 mas => | ~ 0.2 pc @ M31 | => the nearest spiral |
As an example, the figure below show adaptive optics VLT images, in the 1 to 2.5 um range, of the central parsecs of some of the nearest galaxies in Southern Hemisphere. These galaxies are part of a international observational program, PARSEC, with VLT and Keck aimed at uncovering the central few parsecs of the
brightest and closest galaxies in the local Universe.
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In each panel, quoted values at the centre of the figure indicate the spatial resolution in physical scales (FWHM < 0.1 arcsec), and represent an upper limit to the nucleus size in each galaxy, In two cases so far, the nucleus has been resolved in the IR: Circinus (FWHM ~ 2 pc, at 2µm, Prieto et al. 2004, and at 10 µm, Tristram et al. 2007), and NGC 1068 (~2 x1 pc at 10 µm , Jaffe et al. 2004 and at 2 µm, Weigelt et al. 2004.)
... and even closer: resolving stars in Andromeda
Andromeda, the nearest spiral galaxy to Earth, will be seen with FRIDA down to scales of 1/6 of pc at 2 µm. At these esolutions, it shall be possible to resolve stars down to the tip of the RGB and AGB stars, which in Andromeda are brigther than K<18 mag. Moreover, RGB stars span a wide range of ages, 106 to 109 yr, their detection across Andromeda shall make them suitable candles for:
=> tracing the different stellar population in the halo, disk, bulge, arms, from which ages could be estimated and thus, clues on Andromeda history formation be derived.
=> tracing chemical enrichment across the galaxy.
=> kinematics of individual RGB stars => accurate determination of galaxy potential.
Spitzer images of Andromeda -above: NASA/JPL/Caltech/P.Barmby, Harward-Smithsonian
CfA, PR 2006 - reveal a large concentration of dust across the disk. FRIDA will be
able to see through this dust and explore tiny regions of the galaxy with a resolution 25 times larger than that of Spitzer.
- The panoramic view:
FRIDA => Diffraction limit imaging in JHK on 40” x 40“ FoV
- The microscopic view:
FRIDA => 2D spec with 45 mas resolution and spectral resolution down to R= 10 km / s
FRIDA will allow us both, parsec-scale studies of a
large number of galactic sources (HII regions, HH objects,
binaries, planetary nebulae, stellar disks …) but also accurate
spectral diagnosis of many of these sources (stellar atmospheres,
metalicities, ages) thanks to its very high spectral
resolution.
The figure below illustrates the case of ultra compact
HII regions. These are very dusty
regions where massive stars come to light. The new born stars are
embedded in their parental cloud and therefore the mechanisms by which
star formation sparks can only be explored in the IR.
The left panel shows an optical image of the compact HII G61.48+0.09,
the right panel shows the same region observed in the IR with the
AO system ALPHA at the Calar Alto observatory. The IR image
uncovers a large number of hidden stars, among which the
brightest, a K=9 mag star is thought to be the lionizing source of
the HII region. FRIDA will provide similar images but with the add-on
of a very accurate spectral characterization of the source with
resolutions of 10 km/s (from E. Puga et al. 2004 A&A 425).
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