Rachael Ainsworth Dublin Institute for Advanced Studies YERAC 2011

 16 GHz radio continuum observations of target sample for the e-MERLIN legacy project on the morphology and time evolution of thermal jets associated with low mass young stars (Rodriguez+).  I will draw correlations between the radio luminosity and a number of global properties for these systems.  These correlations along with the spectral indices for these sources will help place limits on the physical mechanisms responsible for the radio emission.  Future work: e-MERLIN

 Evolutionary Indicators (Hatchell+ 2007) ◦ Bolometric temperature  Class 0: T bol < 70 K, Class I: 70 < T bol < 150 K ◦ Ratio of submm to bolometric luminosity  L bol /L smm > 3000 ◦ Ratio of Spitzer IRAC to submm emission  F 3.6 /F 850 > 0.003

 A form of thermal emission that comes from gas which has been ionized.  Atoms in the gas become ionized when their electrons become stripped or dislodged.  This results in charged particles moving around in an ionized gas.  As this happens, the electrons are accelerated by the charged particles, and the gas cloud emits radiation continuously.  Often called called "free-free" emission because it is produced by free electrons scattering off ions without being captured.

S ν = ν 2 S ν = ν 0.6 S ν = ν -0.1 Optically thick Partially optically thick Optically thin

 Ionized spherical stellar winds (Panagia & Felli 1975)  Ionized collimated winds (Reynolds 1986)  Both models predict a correlation between the radio luminosity and the rate of stellar mass loss, and α = 0.6, where α is the spectral index defined as

L1448, HH 7-11, L1551, L1527, HH 1-2, HH 26 IR, HH 111, NGC 2264, Serpens, L723, L1251

(Scaife+ 2011) log[L 1.8 cm (mJy kpc 2 )] = −(1.74 ± 0.18) + (0.51±0.26)log[L bol (L⊙)] log[L 1.8 cm (mJy kpc 2 )] = − log[L bol (L⊙)]

(Scaife+ 2011) log[L 1.8 cm (mJy kpc 2 )] = −(2.23 ± 0.65) + (0.68±0.62)log[M env (M⊙)] log[L 1.8 cm (mJy kpc 2 )] = − log[M env (M⊙)]

Capabilities include: o Observing bands at GHz, 4-8 GHz, GHz o Resolution 10 to 150 mas o Total bandwidth 4 GHz o Sensitivity ~ 1 μJy o Astrometry, polarimetry, spectroscopy o Image the jet launch zone to look for clues as to how jets from young stars are generated. o Measure the strength and direction of the magnetic field in the jet launch zone.