ESA Science & Technology - Publication Archive
[This is an extract of the original abstract.]
- Hubble Legacy Archive - Data Release One
- The WFC3 Slitless Spectroscopy Simulator aXeSIMweb
- Why Should We Bother to Communicate Astronomy?
- Tiny Tim PSF Simulator - with WFC3 Support
- Hubble News Update
- ST-ECF Pre-Release of NICMOS Grism Data
- Simulating Slitless Spectroscopic Images with aXeSIM
- Virtual Observatory Services at the ST-ECF
- Inside the ESA/Hubble Internship Programme
We observed an almost featureless transmission spectrum between 550 and 1050 nm, with no indication of the expected sodium or potassium atomic absorption features. Comparison of our results with the transit radius observed in the near and mid-infrared (2-8 micron), and the slope of the spectrum, suggest the presence of a haze of sub-micron particles in the upper atmosphere of the planet.
High redshift galaxies selected on the basis of their strong Lyman-alpha emission tend to be young ages and small physical sizes. We show this by analyzing the spectral energy distribution (SED) of 9 Lyman-alpha emitting (LAE) galaxies at 4.0 < z < 5.7 in the Hubble Ultra Deep Field (HUDF). Rest-frame UV to optical 700A < lambda < 7500A luminosities, or upper limits, are used to constrain old stellar populations. We derive best fit, as well as maximally massive and maximally old, properties of all 9 objects. We show that these faint and distant objects are all very young, being most likely only a few millions years old, and not massive, the mass in stars being ~106-108 MSun. Deep Spitzer Infrared Array Camera (IRAC) observations of these objects, even in cases where objects were not detected, were crucial in constraining the masses of these objects. The space density of these objects, ~1.25x10-4 Mpc-3 is comparable to previously reported space density of LAEs at moderate to high redshifts. These Lyman-alpha galaxies show modest star formation rates of ~8 MSun yr-1, which is nevertheless strong enough to have allowed these galaxies to assemble their stellar mass in less than a few x106 years. These sources appear to have small physical sizes, usually smaller than 1 Kpc, and are also rather concentrated. They are likely to be some of the least massive and youngest high redshift galaxies observed to date.
- Hubble Status
- Spectral Signal-to-Noise
- Staff Update
- Re-activation of the ACS Solar Blind Channel (SBC)
- Scisoft VII - with VO Support
- Hubblecast: A Video Podcast from ST-ECF
- Hubble's Bequest to Astronomy
- PHLAG: Pipeline for Hubble Legacy Archive Grism Data
- ESA-ESO Topical Science Working Groups
- Solar System Bodies in Hubble Observations
- Staff Update
- Communication of the "Pluto Affair"
- NASA Award for ST-ECF Staff
- The International Year of Astronomy 2009
- Servicing Mission 4