Pete menici Array Science Center

Truth or Consequences, NM, United States

Pete menici Array Science Center

Truth or Consequences, NM, United States

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Decarli R.,Max Planck Institute for Astronomy | Walter F.,Max Planck Institute for Astronomy | Neri R.,IRAM | Bertoldi F.,University of Bonn | And 12 more authors.
Astrophysical Journal | Year: 2012

We present secure [N II]205 μm detections in two millimeter-bright, strongly lensed objects at high redshift, APM08279+5255 (z = 3.911) and MM18423+5938 (z = 3.930), using the IRAM Plateau de Bure Interferometer. Due to its ionization energy [N II]205 μm is a good tracer of the ionized gas phase in the interstellar medium. The measured fluxes are S([N II]205 μm) = (4.8 ± 0.8)Jykms-1 and (7.4 ± 0.5)Jykms-1, respectively, yielding line luminosities of L([N II]205 μm) = (1.8 ± 0.3) × 109 μ-1 L for APM08279+5255 and L([N II]205 μm) = (2.8 ± 0.2) × 109 μ-1 L for MM18423+5938. Our high-resolution map of the [N II]205 μm and 1mm continuum emission in MM18423+5938 clearly resolves an Einstein ring in this source and reveals a velocity gradient in the dynamics of the ionized gas. A comparison of these maps with high-resolution EVLA CO observations enables us to perform the first spatially resolved study of the dust continuum-to-molecular gas surface brightness (Σ FIRΣN CO, which can be interpreted as the star formation law) in a high-redshift object. We find a steep relation (N = 1.4 ± 0.2), consistent with a starbursting environment. We measure a [N II]205 μm/FIR luminosity ratio in APM08279+5255 and MM18423+5938 of 9.0 × 10-6 and 5.8 × 10-6, respectively. This is in agreement with the decrease of the [N II]205 μm/FIR ratio at high FIR luminosities observed in local galaxies. © 2012. The American Astronomical Society. All rights reserved..


Lestrade J.-F.,Paris Observatory | Carilli C.L.,Pete menici Array Science Center | Thanjavur K.,Canada France Hawaii Telescope Corporation | Thanjavur K.,University of Victoria | And 5 more authors.
Astrophysical Journal Letters | Year: 2011

We present high-resolution imaging of the low-order (J = 1 and 2) CO line emission from the z = 3.93 submillimeter galaxy (SMG) MM18423+5938 using the Expanded Very Large Array, and optical and near-IR imaging using the Canada-France-Hawaii Telescope. This SMG with a spectroscopic redshift was thought to be gravitationally lensed given its enormous apparent brightness. We find that the CO emission is consistent with a complete Einstein ring with a major axis diameter of 14, indicative of lensing. We have also identified the lensing galaxy as a very red elliptical coincident with the geometric center of the ring and estimated its photometric redshift z 1.1. A first estimate of the lens magnification factor is m 12. The luminosity L′CO(1 - 0) of the CO(1-0) emission is 2.71 0.38 × 1011 m -1Kkms-1 pc2, and, adopting the commonly used conversion factor for ultraluminous infrared galaxies (ULIRGs), the molecular gas mass is M(H2) = 2.2 × 1011 m -1 M⊙, comparable to unlensed SMGs if corrected by m 12. Our revised estimate of the far-IR luminosity of MM18423+5938 is 2 × 10 13 m -1 < L FIR < 3 × 10 14 m -1 L⊙, comparable to that of ULIRGs. Further observations are required to quantify the star formation rate in MM18423+5938 and to constrain the mass model of the lens in more detail. © 2011. The American Astronomical Society. All rights reserved.


Lentati L.,Astrophysics Group | Carilli C.,Astrophysics Group | Carilli C.,Pete menici Array Science Center | Alexander P.,Astrophysics Group | And 2 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2014

A new Bayesian method for performing an image domain search for line-emitting galaxies is presented. The method uses both spatial and spectral information to robustly determine the source properties, employing either simple Gaussian, or other physically motivated models whilst using the evidence to determine the probability that the source is real. In this paper, we describe the method, and its application to both a simulated data set, and a blind survey for cold molecular gas using observations of the Hubble Deep Field-North taken with the Plateau de Bure Interferometer. We make a total of six robust detections in the survey, five of which have counterparts in other observing bands. We identify the most secure detections found in a previous investigation, while finding one new probable line source with an optical ID not seen in the previous analysis. This study acts as a pilot application of Bayesian statistics to future searches to be carried out both for low-J CO transitions of high-redshift galaxies using the Jansky Very Large Array (JVLA), and at millimetre wavelengths with Atacama Large Millimeter/submillimeter Array (ALMA), enabling the inference of robust scientific conclusions about the history of the molecular gas properties of star-forming galaxies in the Universe through cosmic time. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.


Decarli R.,Max Planck Institute for Astronomy | Walter F.,Max Planck Institute for Astronomy | Yang Y.,Max Planck Institute for Astronomy | Carilli C.L.,Pete menici Array Science Center | And 8 more authors.
Astrophysical Journal | Year: 2012

We search for extended Lyα emission around two z > 6 quasars, SDSS J1030+0524 (z = 6.309) and SDSS J1148+5251 (z = 6.419) using Wide Field Camera 3 narrowband filters on board the Hubble Space Telescope. For each quasar, we collected two deep, narrowband images, one sampling the Lyα line+continuum at the quasar redshifts and one of the continuum emission redward of the line. After carefully modeling the point-spread function, we find no evidence for extended Lyα emission. These observations set 2σ limits of L(Lyα, extended) <3.2 × 1044ergs-1 for J1030+0524 and L(Lyα, extended) <2.5 × 1044 ergs -1 for J1148+5251. Given the star formation rates typically inferred from (rest-frame) far-infrared measurements of z ∼ 6 quasars, these limits are well below the intrinsic bright Lyα emission expected from the recombination of gas photoionized by the quasars or by the star formation in the host galaxies, and point toward significant Lyα suppression or dust attenuation. However, small extinction values have been observed along the line of sight to the nuclei, thus reddening has to be coupled with other mechanisms for Lyα suppression (e.g., resonance scattering). No Lyα emitting companions are found, down to a 5σ sensitivity of ∼1 × 10 -17ergs-1cm-2 arcsec-2 (surface brightness) and ∼5 × 10-17ergs-1cm-2 (assuming point sources). © 2012. The American Astronomical Society. All rights reserved.


Decarli R.,Max Planck Institute for Astronomy | Walter F.,Max Planck Institute for Astronomy | Carilli C.,Pete menici Array Science Center | Bertoldi F.,University of Bonn | And 7 more authors.
Astrophysical Journal Letters | Year: 2014

We study the properties of the interstellar medium in the interacting system BR1202-0725 at z = 4.7 via its [N II] and [C II] fine-structure line emission. This system consists of a QSO, a sub-mm galaxy (SMG), and two Lyα emitters (LAEs). Such a diversity in galaxy properties makes BR1202-0725 a unique laboratory of star formation and galaxy evolution at high redshift. We present ionized nitrogen ([N II] 205 μm) observations of this system, obtained with the IRAM Plateau de Bure Interferometer. We find no [N II] emission at the quasar location, but tentative [N II] line detections associated with the SMG and one of the LAEs. Together with available ionized carbon ([C II] 158 μm) Atacama Large Millimeter Array observations of this system, we find the following: the [C II]/[N II] luminosity ratio is >5.5 for the QSO and the SMG, but it is as low as ∼2 in the LAE, suggesting that, in this source, most of the [C II] emission is associated with the ionized medium (H II regions) rather than the neutral one (photon-dominated regions). This study demonstrates the importance of combined studies of multiple fine-structure lines in order to pin down the physical properties of the interstellar medium in distant galaxies. © 2014. The American Astronomical Society. All rights reserved.


Decarli R.,Max Planck Institute for Astronomy | Walter F.,Max Planck Institute for Astronomy | Carilli C.,Pete menici Array Science Center | Riechers D.,Cornell University | And 20 more authors.
Astrophysical Journal | Year: 2014

We present a molecular line scan in the Hubble Deep Field North (HDF-N) that covers the entire 3 mm window (79-115 GHz) using the IRAM Plateau de Bure Interferometer. Our CO redshift coverage spans z ≲ 0.45, 1 ≲ z ≲ 1.9 and all z ≳ 2. We reach a CO detection limit that is deep enough to detect essentially all z > 1 CO lines reported in the literature so far. We have developed and applied different line-searching algorithms, resulting in the discovery of 17 line candidates. We estimate that the rate of false positive line detections is 2/17. We identify optical/NIR counterparts from the deep ancillary database of the HDF-N for seven of these candidates and investigate their available spectral energy distributions. Two secure CO detections in our scan are identified with star-forming galaxies at z = 1.784 and at z = 2.047. These galaxies have colors consistent with the "BzK" color selection and they show relatively bright CO emission compared with galaxies of similar dust continuum luminosity. We also detect two spectral lines in the submillimeter galaxy HDF 850.1 at z = 5.183. We consider an additional nine line candidates as high quality. Our observations also provide a deep 3 mm continuum map (1σ noise level = 8.6 μJy beam-1). Via a stacking approach, we find that optical/MIR bright galaxies contribute only to <50% of the star formation rate density at 1 < z < 3, unless high dust temperatures are invoked. The present study represents a first, fundamental step toward an unbiased census of molecular gas in "normal" galaxies at high-z, a crucial goal of extragalactic astronomy in the ALMA era. © 2014. The American Astronomical Society. All rights reserved..


Walter F.,Max Planck Institute for Astronomy | Decarli R.,Max Planck Institute for Astronomy | Sargent M.,University Paris Diderot | Carilli C.,Pete menici Array Science Center | And 19 more authors.
Astrophysical Journal | Year: 2014

We present direct constraints on the CO luminosity function at high redshift and the resulting cosmic evolution of the molecular gas density, ρH2 (z), based on a blind molecular line scan in the Hubble Deep Field North (HDF-N) using the IRAM Plateau de Bure Interferometer. Our line scan of the entire 3 mm window (79-115 GHz) covers a cosmic volume of 7000 Mpc3, and redshift rangesz < 0.45, 1.01 < z < 1.89 andz > 2.We use the rich multiwavelength and spectroscopic database of the HDF-N to derive some of the best constraints on CO luminosities in high redshift galaxies to date. We combine the blind CO detections in our molecular line scan (presented in a companion paper) with stacked CO limits from galaxies with available spectroscopic redshifts (slit or mask spectroscopy from Keck and grism spectroscopy from the Hubble Space Telescope) to give first blind constraints on high-z CO luminosity functions and the cosmic evolution of the H2 mass density ρH2 (z) out to redshifts z 3. A comparison to empirical predictions of ρH2 (z) shows that the securely detected sources in our molecular line scan already provide significant contributions to the predicted ρH2 (z) in the redshift bins (z) 1.5 and (z) 2.7. Accounting for galaxies with CO luminosities that are not probed by our observations results in cosmic molecular gas densities ρH2 (z) that are higher than current predictions.We note, however, that the current uncertainties (in particular the luminosity limits, number of detections, as well as cosmic volume probed) are significant, a situation that is about to change with the emerging ALMA observatory. © 2014. The American Astronomical Society. All rights reserved.


Decarli R.,Max Planck Institute for Astronomy | Walter F.,Max Planck Institute for Astronomy | Carilli C.,Pete menici Array Science Center | Riechers D.,Cornell University
Proceedings of the International Astronomical Union | Year: 2014

Our understanding of galaxy evolution has traditionally been driven by pre-selection of galaxies based on their broad-band continuum emission. This approach is potentially biased, in particular against gas-rich systems at high-redshift which may be dust-obscured. To overcome this limitation, we have recently concluded a blind CO survey at 3mm in a region of the Hubble Deep Field North using the IRAM Plateau de Bure Interferometer. Our study resulted in 1) the discovery of the redshift of the bright SMG HDF850.1 (z = 5.183); 2) the discovery of a bright line identified as CO(2-1) arising from a BzK galaxy at z = 1.785, and of other 6 CO lines associated with various galaxies in the field; 3) the detection of a few lines (presumably CO(3-2) at z ∼ 2) with no optical/NIR/MIR counterparts. These observational results allowed us to expand the parameter space of galaxy properties probed so far in high-z molecular gas studies. Most importantly, we could set first direct constraints on the cosmic evolution of the molecular gas content of the universe. The present study represents a first, fundamental step towards an unbiased census of molecular gas in 'normal' galaxies at high-z, a crucial goal of extragalactic astronomy in the ALMA era. © International Astronomical Union 2015.

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