-
[show abstract]
[hide abstract]
ABSTRACT: The radio-quiet quasar BR1202-0725 (z=4.695) is a remarkable source with a
bright Northwest (NW) companion detected at submm and radio wavelengths but
invisible in the optical. In the absence of amplification by gravitational
lensing, BR1202-0725 would be the most luminous binary CO and FIR source in the
Universe. In this paper, we report observations with the IRAM Plateau de Bure
interferometer of BR1202-0725 in the redshifted emission of the CO(5-4) and
(7-6) lines, the [C I](3P2-3P1) line, a high angular resolution (0.3 x 0.8
arcsec) 1.3 mm map of the rest-frame, far-IR dust continuum, and a search for
the CO(11-10) line. We compare these results with recent ALMA data in the [C
II] line. Both the quasar host galaxy and its NW companion are spatially
resolved in the molecular line emission and the dust continuum. The CO profile
of the NW companion is very broad with a full width at half maximum of 1000 +/-
130 km/s, compared to 360 +/- 40 km/s for the quasar host galaxy to the
Southeast (SE). The difference in linewidths and center velocities, and the
absence of any lens candidate or arc-like structure in the field, at any
wavelength, show that the obscured NW galaxy and the SE quasar host galaxy
cannot be lensed images of the same object. Instead, we find morphological and
kinematic evidence for sub-structures in both the NW and SE sources. We
interpret these results as strong indications that the BR1202-0725 complex is a
group of young, interacting, and highly active starburst galaxies.
07/2012;
-
[show abstract]
[hide abstract]
ABSTRACT: We report on sensitive observations of the CO(7-6) and CI(2-1) transitions in
the z=2.79 QSO host galaxy RXJ0911.4+0551 using the IRAM Plateau de Bure
interferometer (PdBI). Our extremely high signal to noise spectra combined with
the narrow CO line width of this source (FWHM = 120 km/s) allows us to estimate
sensitive limits on the space-time variations of the fundamental constants
using two emission lines. Our observations show that the CI and CO line shapes
are in good agreement with each other but that the CI line profile is of order
10% narrower, presumably due to the lower opacity in the latter line. Both
lines show faint wings with velocities up to +/-250 km/s, indicative of a
molecular outflow. As such the data provide direct evidence for negative
feedback in the molecular gas phase at high redshift. Our observations allow us
to determine the observed frequencies of both transitions with so far unmatched
accuracy at high redshift. The redshift difference between the CO and CI lines
is sensitive to variations of dF/F with F=alpha^2/mu where alpha is the fine
structure constant and mu the proton-to-electron mass ratio. We find dF/F=6.9
+/-3.7 x 10^-6 at a lookback time of 11.3 Gyr, which within the uncertainties,
is consistent with no variations of the fundamental constants.
04/2012;
-
[show abstract]
[hide abstract]
ABSTRACT: Observations of 12CO at high redshift indicate rapid metal enrichment in the nuclear regions of at least some galaxies in the early universe. However, the enrichment may be limited to nuclei that are synthesized by short-lived massive stars, excluding classical secondary nuclei like 13CO. Testing this idea, we tentatively detect the 13CO J=3-2 line at a level of 0.3 Jy km/s toward the Cloverleaf Quasar at redshift 2.5. This is the first observational evidence for 13CO at high redshift. The 12CO/13CO J=3-2 luminosity ratio is with at least 40 much higher than ratios observed in molecular clouds of the Milky Way and in the ultraluminous galaxy Arp 220, but may be similar to that observed toward NGC 6240. Large Velocity Gradient (LVG) models simulating seven 12CO transitions and the 13CO line yield 12CO/13CO abundance ratios in excess of 100 for the Cloverleaf. It is possible that the measured ratio is affected by a strong submillimeter radiation field, which reduces the contrast between the 13CO line and the background. It is more likely, however, that the ratio is caused by a real deficiency of 13CO. A potential conflict with optical data, indicating high abundances also for secondary nuclei in quasars of high redshift, may be settled if the bulk of the CO emission is originating sufficiently far from the active galactic nucleus. Comment: 7 pages, 5 figures, accepted for publication in A&A (Main Journal)
04/2010;
-
[show abstract]
[hide abstract]
ABSTRACT: We report the redshift of a distant, highly obscured submm galaxy (SMG), based entirely on the detection of its CO line emission. We have used the newly commissioned Eight-MIxer Receiver (EMIR) at the IRAM 30m telescope, with its 8 GHz of instantaneous dual-polarization bandwidth, to search the 3-mm atmospheric window for CO emission from SMMJ14009+0252, a bright SMG detected in the SCUBA Lens Survey. A detection of the CO(3--2) line in the 3-mm window was confirmed via observations of CO(5--4) in the 2-mm window. Both lines constrain the redshift of SMMJ14009+0252 to z=2.9344, with high precision (dz=2 10^{-4}). Such observations will become routine in determining redshifts in the era of the Atacama Large Millimeter/submillimeter Array (ALMA). Comment: 5 pages, 3 figures, accepted by ApJL
09/2009;
-
[show abstract]
[hide abstract]
ABSTRACT: We present CO (2-1) maps of the molecular gas associated with the inner parts of the anomalous arms of NGC 4258. The CO emission is found to be well correlated with the arms, and it extends out to ~2 kpc from the center. Together with CO (1-0) and (3-2) measurements and the detection of 13CO (1-0) and CS (3-2) toward the center of NGC 4528, we derive the physical conditions of the molecular gas along these arms and analyze in detail the dynamics of the gas. The molecular gas is relatively dense (103 cm–3 on average) and warm (50-100 K), with a total H2 mass of 109 M. The CO distribution shows a characteristic S-shaped morphology, along which the molecular gas is found to move toward the nucleus, not away from it.Contrary to previous interpretations, we suggest that the anomalous arms in NGC 4258 trace the gas flow due to a bar rather than being the manifestation of a jet. Both the S-shaped morphology and the velocity dispersion revealed by the present CO measurements are characteristic of barred galaxies. In the bar of NGC 4258, most of the gas is molecular, not atomic. The molecular gas is bounded by the sharp leading edge traced in the radio continuum that is probably the bar shock with its compressed magnetic field. The shocked Hα emission along the anomalous arms is probably a secondary manifestation of the bar shock. In the X-ray-emitting gas associated with the anomalous arms, the temperature is consistent with velocities and densities in bar-shock fronts rather than in jets of radio galaxies. We suggest that the X-rays, like the radio continuum and optical line emission, are produced via the bar shock and are unrelated to a jet from the black hole. The large extension of both the Hα and radio emission out to a projected distance of ~7 kpc probably trace the hot (106 K) thermal X-ray gas produced by the bar shocks, which leaks out of the bar structure and eventually escapes from the disk in the z-direction. We predict that, with sufficient sensitivity and angular resolution, similar radio and X-ray emission will also be found in the shock fronts of other, more distant, barred galaxies.
The Astrophysical Journal 01/2009; 473(1):219. · 6.02 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: With the IRAM interferometer, we detected the lines of CO (4-3) and CO (9-8) from the recently discovered broad absorption line quasar APM 08279+5255. The molecular lines are at a redshift of 3.911, which we take to be the true cosmological redshift of the quasar's host galaxy. This means that the quasar emission lines at z=3.87 are blueshifted by a kinematic component of -2500 km s−1 and, along with the broad absorption lines, are probably emitted in the quasar's wind or jet, moving toward us. The CO line ratios suggest that the molecular gas is at a temperature of ~200 K, at a density of ~4000 cm−3. We also detected the dust emission at 94 and 214 GHz (with emitted wavelengths of 650 and 290 μm). The spectral index of the millimeter/submillimeter continuum is 3.2, indicating that the dust emission is optically thin in this part of the spectrum. The extremely high CO and dust luminosities suggest magnification by gravitational lensing. Using the optical extent and our limit on the size of the CO region, we estimate a magnification of 7-30 for the CO lines and the far-IR continuum and 14-60 for the optical/UV. In this interpretation, the molecular gas and dust are in a nuclear disk of radius 90-270 pc around the quasar. The quasar is 25-100 times stronger than, but otherwise resembles, the nucleus of Mrk 231.
The Astrophysical Journal 12/2008; 513(1):L1. · 6.02 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We detect HCN J = 5-4 emission from the ultraluminous quasar APM 08279+5255 at z = 3.911 using the IRAM Plateau de Bure Interferometer. This object is strongly gravitationally lensed, yet still thought to be one of the most intrinsically luminous objects in the universe. The new data imply a line luminosity L = (4.0 ± 0.5) × 1010 K km s-1 pc2. The ~440 km s-1 FWHM of the HCN J = 5-4 line matches that of the previously observed high-J CO lines in this object and suggests that the emission from both species emerges from the same region: a warm, dense circumnuclear disk. Simple radiative transfer models suggest an enhanced abundance of HCN relative to CO in the nuclear region of APM 08279+5255, perhaps due to increased ionization, or possibly the selective depletion of oxygen. The ratio of far-infrared luminosity to HCN luminosity is at the high end of the range found for nearby star-forming galaxies, but is comparable to that observed in the few high-redshift objects detected in the HCN J = 1-0 line. This is the first clear detection of high-J HCN emission redshifted into the 3 mm atmospheric window.
The Astrophysical Journal 12/2008; 634(1):L13. · 6.02 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We report the detection of the CO 4-3, 6-5, 9-8, 10-9, and 11-10 lines in the Broad Absorption Line quasar APM08279+5255 at z=3.9 using the IRAM 30m telescope. We also present IRAM PdBI high spatial resolution observations of the CO 4-3 and 9-8 lines, and of the 1.4mm dust radiation as well as an improved spectrum of the HCN(5-4) line. Unlike CO in other QSO host galaxies, the CO line SED of APM08279+5255 rises up to the CO(10-9) transition. The line fluxes in the CO ladder and the dust continuum fluxes are best fit by a two component model, a "cold" component at ~65K with a high density of n(H2)= 1x10^5 cm^-3, and a "warm", ~220K component with a density of 1x10^4 cm^-3. We show that IR pumping via the 14 micron bending mode of HCN is the most likely channel for the HCN excitation. From our models we find, that the CO(1-0) emission is dominated by the {\it dense} gas component which implies that the CO conversion factor is higher than usually assumed for high-z galaxies with alpha~5 SM/(K km/s pc^2). Using brightness temperature arguments, the results from our high-resolution mapping, and lens models from the literature, we argue that the molecular lines and the dust continuum emission arise from a very compact (r~100-300 pc), highly gravitationally magnified (m= 60-110) region surrounding the central AGN. Part of the difference relative to other high-$z$ QSOs may therefore be due to the configuration of the gravitational lens, which gives us a high-magnification zoom right into the central 200-pc radius of APM08279+5255 where IR pumping plays a significant role for the excitation of the molecular lines. Comment: 18 pages, 14 figures, accepted for publication in A&A
02/2007;
-
[show abstract]
[hide abstract]
ABSTRACT: We present a detection of [CI] line emission in the lensed quasar APM 08279+5255 at z=3.91 using the IRAM Plateau de Bure interferometer. The [CI] line velocity and width are similar to the values of previously detected high-J CO and HCN lines in this source, suggesting that the emission from all of these species arises from the same region. The apparent luminosity of the [CI] line is L'(CI) = (3.1 +/- 0.4)x10^10 K km/s pc^2, which implies a neutral carbon mass, M(CI) = (4.4+/-0.6)/m x10^7 M_sun, where m is the lensing magnification factor. The [CI] line luminosity is consistent with the large molecular gas mass inferred from the nuclear CO line luminosity ~10^11 /m M_sun. We also present an upper limit on the H2O line luminosity in APM 08279+5255 of, L'(H2O) < 1.8x10^10 K km/s pc^2 (3-sigma).
08/2006;
-
[show abstract]
[hide abstract]
ABSTRACT: We detect HCN J=5-4 emission from the ultraluminous quasar APM08279+5255 at z=3.911 using the IRAM Plateau de Bure interferometer. This object is strongly gravitationally lensed, yet still thought to be one of the most intrinsically luminous objects in the Universe. The new data imply a line luminosity L'_HCN(J=5-4) = 4.0+/-0.5 x 10^(10) K km/s pc^2. The ~440 km/s full width half maximum of the HCN J=5-4 line matches that of the previously observed high-J CO lines in this object and suggests that the emission from both species emerges from the same region: a warm, dense circumnuclear disk. Simple radiative transfer models suggest an enhanced abundance of HCN relative to CO in the nuclear region of APM08279+5255, perhaps due to increased ionization, or possibly the selective depletion of oxygen. The ratio of far-infrared luminosity to HCN luminosity is at the high end of the range found for nearby star forming galaxies, but comparable to that observed in the few high redshift objects detected in the HCN J=1-0 line. This is the first clear detection of high-J HCN emission redshifted into the 3-millimeter atmospheric window. Comment: Accepted for publication in ApJL
10/2005;
-
[show abstract]
[hide abstract]
ABSTRACT: Using the IRAM 30m telescope, we report the detection of the CO(3--2), CO(4--3), CO(5--4) and CO(6--5) lines in the gravitational lensed submm galaxy SMM J16359+6612 at z=2.5. The CO lines have a double peak profile in all transitions. From a Gaussian decomposition of the spectra we show that the CO line ratios, and therefore the underlying physical conditions of the gas, are similar for the blue and the redshifted component. The CO line Spectral Energy Distribution (SED; i.e. flux density vs. rotational quantum number) turns over already at the CO(5--4) transition which shows that the molecular gas is less excited than in nearby starburst galaxies and high--z QSOs. This difference mainly arises from a lower average H2 density, which indicates that the gas is less centrally concentrated than in nuclear starburst regions in local galaxies. We suggest that the bulk of the molecular gas in SMM J16359+6612 may arise from an overlap region of two merging galaxies. The low gas density and clear velocity separation may reflect an evolutionary stage of the merger event that is in between those seen in the Antennae and in the more evolved ultraluminous infrared galaxies (ULIRGs) like e.g. Mrk231. Comment: 5 pages, 3 figures, accepted by A&A Letters
08/2005;
-
[show abstract]
[hide abstract]
ABSTRACT: Using the IRAM 30m telescope we detected the lower fine structure line of neutral carbon towards three high--redshift sources: IRAS FSC10214 (z=2.3), SMMJ14011+0252 (z=2.5) and H1413+117 (Cloverleaf quasar, z=2.5). SMMJ14011+0252 is the first high--redshift, non--AGN source in which CI has been detected. The CI(1-0) line from FSC10214 is almost an order of magnitude weaker than previously claimed, while our detection in the Cloverleaf is in good agreement with earlier observations. The CI(1-0) linewidths are similar to the CO widths, indicating that both lines trace similar regions of molecular gas on galactic scales. Derived CI masses for all three objects are of order few 10^7 solar masses and the implied CI(1-0)/CO(3-2) line luminosity ratio is about 0.2. This number is similar to values found in local galaxies. We derive a CI abundance of 5x10^{-5} which implies significant metal enrichment of the cold molecular gas at redshifts 2.5 (age of the universe 2.7 Gyr). We conclude that the physical properties of systems at large lookback times are similar to today's starburst/AGN environments. Comment: 4 pages, 2 figures; accepted by A&A
09/2004;
-
[show abstract]
[hide abstract]
ABSTRACT: We observed the upper fine structure line of neutral carbon, CI(2-1), the CO(3-2) line and the 1.2mm continuum emission from H1413+117 (Cloverleaf quasar, z=2.5) using the IRAM interferometer. Together with the detection of the lower fine structure line (Barvainis etal. 1997), the Cloverleaf quasar is now only the second extragalactic system, besides M82, where both carbon lines have convincingly been detected. Our analysis shows that the carbon lines are optically thin and have an excitation temperature of ~30 K. CO is subthermally excited and the observed line luminosity ratios are consistent with n(H2)=10^(3-4) cm^(-3) at Tkin=30-50 K. Using three independent methods (CI, dust, CO) we derive a total molecular gas mass (corrected for magnification) of M(H2)=1.2+/-0.3*10^(10) SM. Our observations suggest that the molecular disk extends beyond the region seen in CO(7-6) to a zone of more moderately excited molecular gas that dominates the global emission in CI and the low J CO lines. Comment: 5 pages, 3 figures; accepted by A&A
09/2003;
-
D. Downes,
R. Neri,
A. Greve,
S. Guilloteau,
F. Casoli,
D. Hughes,
D. Lutz,
K. M. Menten,
D. J. Wilner,
P. Andreani, [......],
R. G. Mann,
Y. Mellier,
S. Oliver,
J. Peacock,
D. Rigopoulou,
M. Rowan-Robinson,
P. Schilke,
S. Serjeant,
L. J. Tacconi,
M. Wright
[show abstract]
[hide abstract]
ABSTRACT: The IRAM interferometer has been used to detect the submm source HDF 850.1 found by Hughes et al. (1998) in the Hubble Deep Field. The flux density measured at 1.3mm is 2.2 mJy, in agreement with the flux density measured at the JCMT. The flux densities and upper limits measured at 3.4, 2.8, 1.3, 0.85, and 0.45 mm show that the emission is from dust. We suggest that the 1.3mm dust source is associated with the optical arc-like feature, 3-593.0, that has a photometric redshift of about 1.7. If HDF 850.1 is at this redshift and unlensed, its spectral energy distribution, combined with that of 3-593.0, matches closely that of the ultraluminous galaxy VII Zw 31. Another possibility is that the dust source may be gravitationally lensed by the elliptical galaxy 3-586.0 at a redshift of 1.
08/1999;
-
[show abstract]
[hide abstract]
ABSTRACT: Recent claimed or tentative detections of CO emission in damped
Lyα absorbers towards quasars have been found to be spurious. Our
observations, made with the IRAM interferometer, do not suffer from the
potential baseline uncertainties inherent in single dish work.
Currently, CO has not been detected in any QSO Lyα system. The
systems we observed are: PC 1643+4631A, Q 1235+0857, and Q 0836+113.
Astronomy and Astrophysics 04/1996; 309:L43-L46. · 4.59 Impact Factor
-
S. Guilloteau,
J. Delannoy, D. Downes,
A. Greve,
M. Guelin,
R. Lucas,
D. Morris,
S. J. E. Radford,
J. Wink,
J. Cernicharo,
T. Forveille,
S. Garcia-Burillo,
R. Neri,
J. Blondel,
A. Perrigourad,
D. Plathner,
M. Torres
[show abstract]
[hide abstract]
ABSTRACT: The IRAM interferometer on Plateau de Bure has three 15 m diameter
antennas presently equipped with low noise receivers for the 80-115 GHz
band. Baselines extend 160 m north-south and 288 m east-west. There are
two digital cross-correlators, a wide band continuum correlator and a
narrow band spectral correlator. The instrument's high sensitivity is a
result of its relatively large antennas.
Astronomy and Astrophysics 08/1992; 262:624-633. · 4.59 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: HCN(1-0) line emission from the center of the galaxy IC 342 was mapped
with the IRAM interferometer at 2.7-arcsec resolution. Comparison of
this HCN map with other molecular line maps of similar resolution is
used to determine molecular line ratios on a scale of 20 pc in a massive
galaxy other than the Milky Way. In the five main clouds within 100 pc
of IC 342's nucleus, the CO(1-0)/HCN(1-0) intensity ratio is 7 +/- 2 and
is at least twice as high farther out in the minispiral arms. Comparison
with other maps shows the 3.4-mm continuum radiation near the center of
the galaxy at a level of 27 mJy is free-free emission rather than
thermal radiation by dust. Since the free-free continuum is associated
with only one of the dense molecular clouds traced by the HCN, most of
the molecular clouds in the center of IC 342 do not exhibit any massive
star formation activity.
Astronomy and Astrophysics 08/1992; 262:424-432. · 4.59 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Maps with a spatial resolution of 0.26 arcsec x 0.26 arcsec are
presented of the ammonia (2,2) inversion line in absorption against the
continuum source W3(OH). It is shown that the ammonia cloud covers the
western part of the continuum source, coinciding with the OH masers in
front of the continuum. Evidence is also obtained for velocity and line
width gradients within the NH3 cloud. The cloud is found to be clumpy
with some structure on scales of 0.2 arcsec or less, while the sharp
edges of the opacity maps at the boundary of the H II region indicate
that the cloud probably extends as far as the OH masers. In addition, a
high-sensitivity, high-resolution map of the H II region is obtained,
which is found to agree very well with other maps of similar resolution
at wavelengths of 1.0 and 2.0 cm. The high brightness temperatures show
that part of the region is still optically thick at 1.3 cm. These
findings indicate that the NH3 cloud may be a remnant accreting disk,
whose inner part has been ionized by the UV radiation from a star of 50
solar masses.
Astronomy and Astrophysics 08/1983; 126:10-15. · 4.59 Impact Factor
-
Article:
Weak
http://dx.doi.org/10.1051/0004-6361/200912889.
-
[show abstract]
[hide abstract]
ABSTRACT: We report on the first results of an in depth study of the molecular gas properties in three high-redshift sources: IRAS FSC 10214 (z = 2.3), SMMJ14011+0252 (z = 2.5) and H1413+117 (Cloverleaf quasar, z = 2.5). Our analysis is based on observations at the IRAM interferometer and the IRAM 30m telescope of atomic carbon and multiple CO lines. Our study shows that the cold molecular gas at large lookback times is already enriched to gas phase abundances similar to those found in the local universe. We find that almost all of the molecular gas in QSOs host galaxies is in form of dense gas at moderate kinetic temperatures concentrated in a compact circum nuclear toroid around the AGN. The pure starburst galaxy SMMJ14011+0252, in contrast, contains additional large amount of molecular gas at much lower density.
Hüttemeister, E., Manthey, E., Bomans, D., Weis, K.: The Evolution of Starbusts, AIP, 401-407 (2005).
