Four Large Programs for NIKA2 in guaranteed time were submitted to the Program Committee for the deadline in September 2016, and one for the March 2017 deadline. All 5 have been rated high by the PC and will be observed. Here, we provide the proposal abstracts together with the list of sources and map sizes. These are "fenced" against new continuum 2mm/1mm mapping projects at the 30m or NOEMA.
The three large programs in Phase I have started observations in October 2017. <15-Dec-2017>
Source list
Phase I
'''Galactic Star Formation with NIKA2 - GASTON (122-16) PI is Nicolas Peretto.'''
Abstract:
The IMF is a fundamental global output of the star formation process, and the question of its origin and universality has been a long-standing open issue. While the base of the IMF (0.1 to 1 Msun) may result from Jeans-like fragmentation of interstellar filaments, the problem of how the most extreme stellar objects (brown dwarfs, intermediate- and high-mass stars) build up their masses remains unsettled. The high-sensitivity and fast mapping capability of the NIKA2 camera offer the unique opportunity to detect large populations of low-brightness sources, and probe star-forming regions as never before. We propose to use this new instrument to: i. perform a complete survey of pre-brown-dwarf cores in two nearby star-forming regions, ii. map the intertwined populations of interstellar filaments and intermediate to high-mass cores within rich galactic plane star-forming regions; iii. use the dual band capability of NIKA2 at 1.2mm and 2mm to constrain the dust properties in a broad range of environments and reduce mass uncertainties by a factor of 3. Altogether, these observations will provide new insight on the earliest stages of star formation across both ends of the stellar IMF.
'''The NIKA2 Cosmological Legacy Survey (N2CLS) (192-16) PIs: Guilaine Lagache, Alexandre Beelen, Nicolas Ponthieu'''
Abstract:
Using 300h of the NIKA2 Guaranteed Time, we will map the star formation at high redshift in two of the most popular fields. N2CLS will reach for the first time the confusion noise at the 30m, in 160 square arcminutes in GOODS-N. In COSMOS, N2CLS sensitivity will at least match or outperform the sensitivity of the S2CLS survey at 850 microns on 0.5 square degree. N2CLS will detect hundreds of dust-obscured optically-faint galaxies during their major episodes of formation in the early universe. It will fully open a new window on the faint and high-redshift dusty Universe and answer the outstanding issue of whether dusty star-formation contributes to early galaxy evolution. It will uniquely probe the transition at z~3-4 of the cosmic star-formation history between the predominantly unobscured growth in the early Universe and the obscured star formation, driven by the build-up of the most massive galaxies during the peak of cosmic assembly. The availability of this uniquely large sample of mm-selected galaxies with superb supporting multi-wavelength data will provide the opportunity to address the history of star formation, dust production and the growth of large-scale structures.
'''High-resolution tSZ observations of a large sample of clusters of galaxies (NIKA2SZ) (199-16) PIs: Frédéric Mayet, Barbara Comis'''
Homepage: NIKA2LPSZ
Abstract:
The development of precision cosmology with clusters of galaxies requires high angular resolution observations to extend the understanding of galaxy clusters towards high redshift. The NIKA2 camera at the IRAM 30 m telescope is the only instrument currently in operation that is suited for this kind of observations, given its resolution, sensitivity and dual-band observation capability. We intend to observe a large sample of clusters of galaxies at high redshift (0.5 < z < 0.9), selected from the Planck and ACT catalogs. We have formed a representative cluster sample for redshift evolution and cosmological studies, with a homogeneous coverage in cluster mass as reconstructed from the integrated Compton parameter. We will use the SZ-dedicated pipeline that we have developed for the SZ observation with the NIKA camera. Our primary objective is to produce unprecedented high-quality deliverables (tSZ maps and pressure profiles) for all clusters of the sample. NIKA2 data will be complemented with ancillary data including X-ray, optical and radio observations. The full dataset will lead to significant improvements on the use of clusters of galaxies to draw cosmological constraints.
Phase II
'''Interpreting the Millimetre Emission of Galaxies with IRAM and NIKA (IMEGIN) (160-16) PI is Jonathan Davies'''
Abstract:
The mm part of the spectrum is one of the least explored parts of a galaxy’s spectral energy distribution (SED), yet it contains emission from three fundamentally important physical processes. These processes are thermal emission from dust, free-free emission from ionized gas and synchrotron emission from charged particles moving in the galactic magnetic field. We are proposing to use the NIKA2 camera to observe a sample of 22 nearby galaxies that also have considerable ancillary data across the SED from the radio to the ultra-violet. We will investigate the dust emissivity, the relationship between the three physical processes and their relation to star formation and the gas-to-dust ratio. As the sample galaxies are of large angular size we will be able to carry out this project in a spatially resolved way and hence investigate the different environments found within galaxies.
'''Probing the B-Field in star-forming Filaments Using NIKA2-Pol (B-FUN) (015-17) PI: Philippe Andre'''
Abstract:
Recent Herschel and Planck observations of Galactic interstellar clouds support a paradigm of star formation in which magnetized filaments play a central role. Herschel results indicate that most cores/stars form in dense, supercritical filaments of ~0.1 pc width, and Planck polarization data suggest that the formation and evolution of these filaments is largely controlled by magnetic fields. The low resolution of Planck polarization data is however insufficient to probe individual cores along filaments and understand the role of B fields in filament evolution and fragmentation. To make decisive progress in this area, we propose a 1.2 mm polarimetric imaging survey with NIKA2-POL of ~8 nearby star-forming filaments spanning a range of line masses from marginally supercritical to highly supercritical. The proposed observations will constrain the role of magnetic fields in channeling matter from filaments to prestellar cores and will determine whether the B field remains roughly perpendicular to the filaments, as observed by Planck on larger scales, or becomes more parallel to the filaments in their dense interior, which would have profound implications for core formation.