| Description |
We propose a uniform survey of the Large Magellanic Cloud (LMC, 8x8.5 degrees), Small Magellanic Cloud (SMC, 5x5 degrees), and the Magellanic bridge (4x3 degrees) in SPIRE 250, 350, 500 um and PACS 100 and 160 um bands, and PACS spectroscopy of key neutral gas regions in order to produce a HERschel Inventory of The Agents of Galaxy Evolution (HERITAGE), the interstellar medium (ISM) and massive stars. Herschel images will provide key insights into the life cycle of galaxies because the far-infrared and submm emission from dust grains is an effective tracer of the coldest ISM dust, the most deeply embedded young stellar objects (YSOs), and the dust ejected over the lifetime of massive stars. The ISM dust map will directly measure dust on a scale size of individual regions (~10pc, ~5-20 K) with column densities >0.85x10^{21} and >6x10^{21} H-atoms cm^{-2} for the LMC and SMC, respectively. Dust emission per beam will be detected for regions with >0.1 Msun at ~25 K, >5 Msun of 10 K. The CII 158, OI 63, 146 and NII 122 um lines in combination with the total far-infrared emission will 1) probe the physical conditions in the warm neutral medium and photodissociation regions, 2) clarify the origin of CII emission in low-metallicity galaxies and 3) constrain the physical conditions of the ISM gas required for star formation. HERITAGE will complete 1) the census of massive YSOs down to >4 Msun Class 0 sources and 2) the inventory of dust injected into the ISM by massive evolved stars and supernova remnants (SNRs). The variation in dust properties discerned from the dust maps and the measurements of the main cooling lines of the SNR shocks will quantify their effect on the interstellar grain size distribution. HERITAGE will create an archival data set that promises a lasting legacy to match current LMC and SMC surveys at other wavelengths. HERITAGE will bridge the gap between Herschel studies of the Milky Way and those of nearby galaxies and provide a template for high red shift galaxies. |
