A survey of galaxies in CO

A large survey of galaxies in the CO (J=1-0) line is presented. Among different types of active galaxies, within the sample, the detection rate is found to be: Starbursts (15 percent), Liners (60 percent), Seyferts (30 percent). A look at the subsample that is located within 40 Mpc (Ho = 75 km s(-1) Mpc(-1) regarding local density of galaxies reveals no substantial difference between detections and non-detections

The Extraordinary Infrared Spectrum of NGC 1222 (Mkn 603)

The infrared spectra of starburst galaxies are dominated by the low-excitation lines of [NeII] and [SIII], and the stellar populations deduced from these spectra appear to lack stars larger than about 35 Msun. The only exceptions to this result until now were low metallicity dwarf galaxies. We report our analysis of the mid-infrared spectra obtained with IRS on Spitzer of the starburst galaxy NGC 1222 (Mkn 603). NGC 1222 is a large spheroidal galaxy with a starburst nucleus that is a compact radio and infrared source, and its infrared emission is dominated by the [NeIII] line. This is the first starburst of solar or near-solar metallicity, known to us, which is dominated by the high-excitation lines and which is a likely host of high mass stars. We model the emission with several different assumptions as to the spatial distibution of the high- and low-excitation lines and find that the upper mass cutoff in this galaxy is 40-100 Msun.Comment: accepted, Astronomical Journal. 29 pp, 4 figures. In replacement version an acknowledgment to NRAO is adde

The Low CO Content of the Extremely Metal Poor Galaxy I Zw 18

We present sensitive molecular line observations of the metal-poor blue compact dwarf I Zw 18 obtained with the IRAM Plateau de Bure interferometer. These data constrain the CO J=1-0 luminosity within our 300 pc (FWHM) beam to be L_CO < 1 \times 10^5 K km s^-1 pc^2 (I_CO < 1 K km s^-1), an order of magnitude lower than previous limits. Although I Zw 18 is starbursting, it has a CO luminosity similar to or less than nearby low-mass irregulars (e.g. NGC 1569, the SMC, and NGC 6822). There is less CO in I Zw 18 relative to its B-band luminosity, HI mass, or star formation rate than in spiral or dwarf starburst galaxies (including the nearby dwarf starburst IC 10). Comparing the star formation rate to our CO upper limit reveals that unless molecular gas forms stars much more efficiently in I Zw 18 than in our own galaxy, it must have a very low CO-to-H_2 ratio, \sim 10^-2 times the Galactic value. We detect 3mm continuum emission, presumably due to thermal dust and free-free emission, towards the radio peak.Comment: 5 pages in emulateapj style, accepted by the Astrophysical Journa

Circadian Timing of Food Intake Contributes to Weight Gain

Studies of body weight regulation have focused almost entirely on caloric intake and energy expenditure. However, a number of recent studies in animals linking energy regulation and the circadian clock at the molecular, physiological, and behavioral levels raise the possibility that the timing of food intake itself may play a significant role in weight gain. The present study focused on the role of the circadian phase of food consumption in weight gain. We provide evidence that nocturnal mice fed a high‐fat diet only during the 12‐h light phase gain significantly more weight than mice fed only during the 12‐h dark phase. A better understanding of the role of the circadian system for weight gain could have important implications for developing new therapeutic strategies for combating the obesity epidemic facing the human population today

Cuando las personas obesas son más pacientes que las personas no obesas. Un estudio post-quirúrgico de individuos en una asociación de pérdida de peso

The main goal of this article is to investigate the rates of delay discounting among obese people treated surgically and belonging to an association of those interested in controlling their weight. We also analyze whether socio-economic status and personality traits explain the existing differences. rates of delay discounting are elicited using real monetary incentives in an economic experiment where subjects are asked to make several choices between a smaller, more immediate reward and larger, more delayed rewards. personality traits are examined using the Five Factor model. interestingly, our results show that obese people display lower discount rates than the reference group. these differences can not be explained by personality traits. We argue that obese people do not have to show larger discount rates. in fact, awareness and commitment, rather than their current bmi, seem to play a more important role in determining this parameter.El objetivo principal de este artículo es investigar las tasas de descuento temporal entre los individuos obesos tratados quirúrgicamente y que pertenecen a una asociación de personas interesadas en controlar su peso. también se analiza si el nivel socio-económico y los rasgos de la personalidad explican las diferencias existentes. las tasas de descuento diferido se obtuvieron utilizando los incentivos monetarios reales en un experimento económico donde a los sujetos se les pide elegir entre una menor y más inmediata recompensa o una recompensa mayor diferida. los rasgos de personalidad son examinados usando el modelo de cinco factores. Curiosamente, nuestros resultados muestran que las personas obesas muestran tasa de descuento menores al grupo de referencia. estas diferencias no pueden explicarse por los rasgos de personalidad. Nosotros sostenemos que la gente obesa no debería mostrar mayores tasas de descuento. De hecho, la conciencia y el compromiso, en lugar de su actual índice de masa corporal, parecen jugar un papel más importante en la determinación de este parámetro

Molecular Gas and Nuclear Activity in Radio Galaxies Detected by IRAS

This paper reports the latest results from a millimeter-wave (CO) spectroscopic survey of IRAS-detected radio galaxies with L_1.4GHz ~ 10^23-28 W/Hz in the redshift range z ~ 0.02-0.15. The IRAS flux-limited sample contains 33 radio galaxies with different radio morphologies and a broad range of infrared luminosities L_IR = 10^9-12 L_sun), allowing for an investigation of (a) whether low-z radio-selected AGN reside in molecular gas-rich host galaxes, and (b) whether the CO properties are correlated with the properties of the host galaxy or the AGN. All of the radio galaxies in Mazzarella et al. (1993) and Mirabel et al. (1989) have been reobserved. Three new CO detections have been made, raising the total number of CO detections to nine and setting the survey detection rate at ~ 25%. Many of the CO lines have double-peaked profiles, and the CO line widths are broad (average Delta v_FWHM ~ 500+/-130 km/s), exceeding the average CO widths of both ultraluminous infrared galaxies (300+/-90 km/s) and Palomar-Green QSOs (260+/-160 km/s), and thus being indicative of massive host galaxies. The CO luminosities translate into molecular gas masses of ~ 0.4-7x10^9 M_sun, however, the 3-sigma CO upper limits for nondetections do not rule out a molecular gas mass as high as that of the Milky Way (~ 3x10^9 M_sun). Optical images of eight out of nine molecular gas-rich radio galaxies show evidence of close companions and/or tidal features. Finally, there is no obvious correlation between radio power and molecular gas mass. However, it is notable that only one F-R II galaxy out of 12 is detected in this CO survey; the remaining detections are of galaxies hosting F-R I and compact radio jets.Comment: LaTex, 33 pages, including 1 jpg figure and 14 postscript figures, ApJS, in press (August 2005

The Molecular ISM of Dwarf Galaxies on Kiloparsec Scales: A New Survey for CO in Northern, IRAS-detected Dwarf Galaxies

We present a new survey for CO in dwarf galaxies using the Kitt Peak 12m telescope. We observed the central regions of 121 northern dwarfs with IRAS detections and no known CO emission. We detect CO in 28 of these galaxies and marginally detect another 16, increasing by about 50% the number of such galaxies known to have significant CO emission. The galaxies we detect are comparable in mass to the LMC, although somewhat brighter in CO and fainter in the FIR. Within dwarfs, we find that the CO luminosity, L_CO, is most strongly correlated with the K-band and the far infrared luminosities. There are also strong correlations with the radio continuum and B-band luminosities, and linear diameter. We suggest that L_CO and L_K correlate well because the stellar component of a galaxy dominates the midplane gravitational field and thus sets the pressure of the atomic gas, which controls the formation of H_2 from HI. We compare our sample with more massive galaxies and find that dwarfs and large galaxies obey the same relationship between CO and the 1.4 GHz radio continuum (RC) surface brightness. This relationship is well described by a Schmidt Law with Sigma_RC proportional to Sigma_CO^1.3. Therefore, dwarf galaxies and large spirals exhibit the same relationship between molecular gas and star formation rate (SFR). We find that this result is robust to moderate changes in the RC-to-SFR and CO-to-H_2 conversion factors. Our data appear to be inconsistent with large (order of magnitude) variations in the CO-to-H_2 conversion factor in the star forming molecular gas. [abridged]Comment: 28 pages, 14 figures, 5 tables, ApJ accepte

Effect of Dust Extinction on Estimating Star Formation Rate of Galaxies: Lyman Continuum Extinction

We re-examine the effect of Lyman continuum ($\lambda \leq 912$ \AA) extinction (LCE) by dust in H {\sc ii} regions in detail and discuss how it affects the estimation of the global star formation rate (SFR) of galaxies. To clarify the first issue, we establish two independent methods for estimating a parameter of LCE ($f$), which is defined as the fraction of Lyman continuum photons contributing to hydrogen ionization in an H {\sc ii} region. One of those methods determines $f$ from the set of Lyman continuum flux, electron density and metallicity. In the framework of this method, as the metallicity and/or the Lyman photon flux increase, $f$ is found to decrease. The other method determines $f$ from the ratio of infrared flux to Lyman continuum flux. Importantly, we show that f \la 0.5 via both methods in many H {\sc ii} regions of the Galaxy. Thus, it establishes that dust in such H {\sc ii} regions absorbs significant amount of Lyman continuum photons directly. To examine the second issue, we approximate $f$ to a function of only the dust-to-gas mass ratio (i.e., metallicity), assuming a parameter fit for the Galactic H {\sc ii} regions. We find that a characteristic $\hat{f}$, which is defined as $f$ averaged over a galaxy-wide scale, is 0.3 for the nearby spiral galaxies. This relatively small $\hat{f}$ indicates that a typical increment factor due to LCE for estimating the global SFR ($1/\hat{f}$) is large ($\sim 3$) for the nearby spiral galaxies. Therefore, we conclude that the effect of LCE is not negligible relative to other uncertainties of estimating the SFR of galaxies.Comment: 18 papges, 11 figures, accepted by Ap

A radio study of the superwind galaxy NGC1482

We present multifrequency radio continuum as well as HI observations of the superwind galaxy NGC1482, with both the GMRT and the VLA. This galaxy has a remarkable hourglass-shaped optical emission line outflow as well as bi-polar soft X-ray bubbles on opposite sides of the galactic disk. The low-frequency, lower-resolution radio observations show a smooth structure. From the non-thermal emission, we estimate the available energy in supernovae, and examine whether this would be adequate to drive the observed superwind outflow. The high-frequency, high-resolution radio images of the central starburst region located at the base of the superwind bi-cone shows one prominent peak and more extended emission with substructure. This image has been compared with the infrared, optical red-continuum, H_alpha, and, soft and hard X-ray images from Chandra. The peak of infrared emission is the only feature which is coincident with the prominent radio peak, and possibly defines the centre of the galaxy. The HI observations with the GMRT show two blobs of emission on opposite sides of the central region. These are rotating about the centre of the galaxy and are located at ~2.4 kpc from it. In addition, these observations also reveal a multicomponent HI-absorption profile against the central region of the radio source, with a total width of ~250 km/s. The extreme blue- and red-shifted absorption components are at 1688 and 1942 km/s respectively, while the peak absorption is at 1836 km/s. This is consistent with the heliocentric systemic velocity of 1850+/-20 km/s, estimated from a variety of observations. We discuss possible implications of these results.Comment: 11 pages, 10 figures, 4 tables, accepted for publication in MNRA

Matching energy intake to expenditure of isocaloric exercise at high- and moderate-intensities

Background Those seeking to manage their bodyweight use a variety of strategies, but the most common approaches involve attempting to exercise more and/or consume fewer calories. A poor comprehension of the energy cost of exercise and the energy content of food may contribute to weight-gain and the poor success rate of exercise weight-loss interventions. Purpose The purpose of this study is to investigate individuals' ability to consciously match energy intake with energy expenditure after isocaloric exercise at moderate and high intensities. Method In a counterbalanced cross-over study design, 14 low- to moderately-active, lean individuals (7 male, 7 female; mean age 23 ± 3 years; mean BMI 22.0 ± 3.2 kg·m− 2) completed both a moderate-intensity (60% VO2max, MOD) and a high-intensity (90% VO2max, HIGH) exercise bout on a treadmill, matched for energy expenditure, EE (450 kcal). Participants were blinded to the intensity and duration of each bout. Thirty minutes post-exercise, participants were presented with a buffet, where they were asked to consume food in an attempt to match energy intake with the energy expended during the exercise bout. This was termed the “matching task,” providing a matching task energy intake value (EIMATCH). Upon finishing the matching task, a verbal estimate of energy expenditure (EST) was obtained before the participant was allowed to return to the buffet to consume any more food, if desired. This intake was covertly measured and added to EIMATCH to obtain an ad libitum intake value (EIAD LIB). Results A significant condition × task interaction showed that, in MOD, EST was significantly lower than EE (298 ± 156 kcal vs. 443 ± 22 kcal, p = 0.01). In the HIGH condition, EE, EIMATCH and EST were similar. In both conditions, participants tended to over-eat to a similar degree, relative to EST, with EIMATCH 20% and 22% greater than EST in MOD and HIGH respectively. Between-condition comparisons demonstrated that EIMATCH and EST were significantly lower in MOD, compared with HIGH (374 ± 220 kcal vs. 530 ± 248 kcal, p = 0.002 and 298 ± 156 kcal vs. 431 ± 129 kcal, p = 0.002 respectively). For both conditions, EIAD LIB was approximately 2-fold greater than EE. Discussion Participants exhibited a strong ability to estimate exercise energy expenditure after high-intensity exercise. Participants appeared to perceive moderate-intensity exercise to be less energetic than an isocaloric bout of high-intensity exercise. This may have implications for exercise recommendations for weight-loss strategies, especially when casual approaches to exercise and attempting to eat less are being implemented