Quasi-Periodic Oscillations and energy spectra from the two brightest Ultra-Luminous X-ray sources in M82

Ultra-Luminous X-ray sources are thought to be accreting black holes that might host Intermediate Mass Black Holes (IMBH), proposed to exist by theoretical studies, even though a firm detection (as a class) is still missing. The brightest ULX in M82 (M82 X-1) is probably one of the best candidates to host an IMBH. In this work we analyzed the data of the recent release of observations obtained from M82 X-1 taken by XMM-Newton. We performed a study of the timing and spectral properties of the source. We report on the detection of (46+-2) mHz Quasi-Periodic Oscillations (QPOs) in the power density spectra of two observations. A comparison of the frequency of these high-frequency QPOs with previous detections supports the 1:2:3 frequency distribution as suggested in other studies. We discuss the implications if the (46+-2) mHz QPO detected in M82 X-1 is the fundamental harmonic, in analogy with the High-Frequency QPOs observed in black hole binaries. For one of the observations we have detected for the first time a QPO at 8 mHz (albeit at a low significance), that coincides with a hardening of the spectrum. We suggest that the QPO is a milli-hertz QPO originating from the close-by transient ULX M82 X-2, with analogies to the Low-Frequency QPOs observed in black hole binaries.Comment: 9 pages (with 4 figures and 4 tables). Accepted for publication in MNRAS (26/09/13

Broad-band X-ray spectral evolution of GX 339-4 during a state transition

We report on X-ray and soft gamma-ray observations of the black-hole candidate GX 339-4 during its 2007 outburst, performed with the RXTE and INTEGRAL satellites. The hardness-intensity diagram of all RXTE/PCA data combined shows a q-shaped track similar to that observed in previous outbursts.The evolution in the diagram suggested that a transition from hard-intermediate state to soft-intermediate state occurred, simultaneously with INTEGRAL observations performed in March. The transition is confirmed by the timing analysis presented in this work, which reveals that a weak type-A quasi-periodic oscillation (QPO) replaces a strong type-C QPO. At the same time, spectral analysis shows that the flux of the high-energy component shows a significant decrease in its flux. However, we observe a delay (roughly one day) between variations of the spectral parameters of the high-energy component and changes in the flux and timing properties. The changes in the high-energy component can be explained either in terms the high-energy cut-off or in terms of a variations in the reflection component. We compare our results with those from a similar transition during the 2004 outburst of GX 339-4.Comment: 8 pages, 6 figures, accepted for publication in MNRAS Main Journa

The NANOGrav 12.5 yr Data Set: Observations and Narrowband Timing of 47 Millisecond Pulsars

We present time-of-arrival (TOA) measurements and timing models of 47 millisecond pulsars observed from 2004 to 2017 at the Arecibo Observatory and the Green Bank Telescope by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). The observing cadence was three to four weeks for most pulsars over most of this time span, with weekly observations of six sources. These data were collected for use in low-frequency gravitational wave searches and for other astrophysical purposes. We detail our observational methods and present a set of TOA measurements, based on narrowband analysis, in which many TOAs are calculated within narrow radio-frequency bands for data collected simultaneously across a wide bandwidth. A separate set of wideband TOAs will be presented in a companion paper. We detail a number of methodological changes, compared to our previous work, which yield a cleaner and more uniformly processed data set. Our timing models include several new astrometric and binary pulsar measurements, including previously unpublished values for the parallaxes of PSRs J1832−0836 and J2322+2057, the secular derivatives of the projected semimajor orbital axes of PSRs J0613−0200 and J2229+2643, and the first detection of the Shapiro delay in PSR J2145−0750. We report detectable levels of red noise in the time series for 14 pulsars. As a check on timing model reliability, we investigate the stability of astrometric parameters across data sets of different lengths. We also report flux density measurements for all pulsars observed. Searches for stochastic and continuous gravitational waves using these data will be subjects of forthcoming publications

The Pit-1/Pou1f1 transcription factor regulates and correlates with prolactin expression in human breast cell lines and tumors

The transcription factor Pit-1/Pou1f1 regulates GH and prolactin (PRL) secretion in the pituitary gland. Pit-1 expression and GH regulation by Pit-1 have also been demonstrated in mammary gland. However, no data are available on the role of Pit-1 on breast PRL. To evaluate this role, several human breast cancer cell lines were transfected with either the Pit-1 expression vector or a Pit-1 small interference RNA construct, followed by PRL mRNA and protein evaluation. In addition, transient transfection of MCF-7 cells by a reporter construct containing the proximal PRL promoter, and ChIP assays were performed. Our data indicate that Pit-1 regulates mammary PRL at transcriptional level by binding to the proximal PRL promoter. We also found that Pit-1 raises cyclin D1 expression before increasing PRL levels, suggesting a PRL-independent effect of Pit-1 on cell proliferation. By using immunohistochemistry, we found a significant correlation between Pit-1 and PRL expression in 94 human breast invasive ductal carcinomas. Considering the possible role of PRL in breast cancer disorders, the function of Pit-1 in breast should be the focus of further research

Hydrogen Susceptibility of Nanostructured Bainitic Steels

Abstract Nanostructured steels with an ultimate tensile strength of 1.6 GPa were produced with austenite content varying from 0 to 35 vol pct. The effect on the mechanical properties was assessed after saturating the steel with hydrogen. Elongation was reduced to 2 to 5 pct and UTS to 65 to 70 pct of prior value. Thermal desorption measurements confirmed the higher solubility of hydrogen in the steel with higher austenite content. The level of hydrogen saturation was found to correlate to the total area of grain boundaries rather than to the volume fraction of retained austenite.This is the final version of the article. It was first available from Springer via http://dx.doi.org/10.1007/s11661-015-3221-

The evolution of the high-energy cut-off in the X-Ray spectrum of the GX 339-4 across a hard-to-soft transition

We report on X-ray observations of the black-hole candidate GX 339-4 during its 2006/2007 outburst. The hardness-intensity diagram of all RXTE/PCA data combined shows a q-shaped track similar to that observed in previous outbursts. The evolution through the HID suggests that in the early phase of the outburst the source underwent a sequence of state transitions, from the hard to the soft state, which is supported by our timing analysis. Broadband (4-200 keV) spectra, fitted with an exponentially cutoff powerlaw, show that the hard spectral component steepens during the transition from the hard to the soft state. The high-energy cutoff decreased monotonically from 120 to 60 keV during the brightening of the hard state, but increased again to 100 keV during the softening in the hard intermediate state. In the short-lived soft intermediate state the cutoff energy was ~ 130 keV, but was no longer detected in the soft state. This is one of the first times that the high-energy cut-off has been followed in such detail across several state transitions. We find that in comparison to several other spectral parameters, the cut-off energy changes more rapidly, just like the timing properties. The observed behaviour of the high energy cutoff of GX 339-4 is also similar to that observed with RXTE-INTEGRAL-Swift during the 2005 outburst of GRO J1655-40. These results constitute a valuable reference to be considered when testing theoretical models for the production of the hard component in these systems.Comment: 16 pages, 8 figures, 5 tables, accepted for publication in MNRAS Main Journa

Suzaku Observations of the Galactic Center Microquasar 1E 1740.7-2942

We present two Suzaku observations of the Galactic center microquasar 1E 1740.7-2942 separated by approximately 700 days. The source was observed on both occasions after a transition to the spectrally hard state. Significant emission from 1E 1740.7-2942 is detected out to an energy of 300 keV, with no spectral break or turnover evident in the data. We tentatively measure a lower limit to the cut-off energy of ~ 380 keV. The spectra are found to be consistent with a Comptonized corona on both occasions, where the high energy emission is consistent with a hard power-law (\Gamma ~ 1.8) with a significant contribution from an accretion disc with a temperature of ~ 0.4 keV at soft X-ray energies. The measured value for the inner radius of the accretion disc is found to be inconsistent with the picture whereby the disc is truncated at large radii in the low-hard state and instead favours a radius close to the ISCO (R_in ~ 10 - 20 R_g).Comment: 8 pages, 4 figures, formatted using emulateapj.cls. Accepted for publication in Ap

FNDC5 is produced in the stomach and associated to body composition

The fibronectin type III domain-containing protein 5 (FNDC5) discovered in 2002 has recently gained attention due to its potential role in protecting against obesity. In rat, no data exist regarding FNDC5 production and regulation in the stomach. The aim of the present work was to determine the expression of FNDC5 in the rat stomach and its potential regulation by body composition. The present data shows FNDC5 gene expression in the gastric mucosa. Immunohistochemical studies found FNDC5 immunopositivity in chief cells of gastric tissue. By the use of three different antibodies FNDC5 was found expressed in gastric mucosa and secreted by the stomach. The rate of gastric FNDC5 secretion parallels the circulating levels of FNDC5. The body fat mass increase after intervention with high fat diet coincided with a decrease in the secretion of FNDC5 from the stomach and a diminution in the FNDC5 circulating levels. In summary, the present data shows, for the first time, the expression of FNDC5 in the stomach of rats and its regulation by body composition, suggesting a potential role of gastric FNDC5 in energy homeostasishis work has been supported by grants from Instituto de Salud Carlos III (PI1202021 and PI15/01272) cofounded by FEDER, Xunta de Galicia (10 PXIB 918 273PR) and Fundación Mutua Madrileña. SB-F is funded by Xunta de Galicia and Universidade de Santiago de Compostela, CF by IDIS (Instituto de Investigación Sanitaria de Santiago de Compostela), CC by Ciber obn and OA-M is funded by the ISCIII/SERGAS thought a research contract “Sara Borrell” (CD14/00091). MP is funded by ISCIII/SERGAS through a research contract “Miguel Servet II”. LMS is a SERGAS-I3SNS researcher. Centro de Investigacion Biomedica en Red Fisiopatología de la Obesidad y Nutrición (CIBERobn) is a iniciative of the Instituto de Salud Carlos III (ISCIII) of Spain which is supported by FEDER fundsS