bluuebunny/crossref_metadata_2025_split huggingface dataset:
The impact of AGN on their host galaxies
Authors: Harrison C. M. 
Published: July 2014

AbstractIn these proceedings I briefly: (1) review the impact (or “feedback”) that active galactic nuclei (AGN) are predicted to have on their host galaxies and larger scale environment, (2) review the observational evidence for or against these predictions and (3) present new results on ionised outflows in AGN. The observational support for the “maintenance mode” of feedback is strong (caveat the details); AGN at the centre of massive halos appear to be regulating the cooling of hot gas, which could in turn control the levels of future star formation (SF) and black hole growth. In contrast, direct observational support for more rapid forms of feedback, which dramatically impact on SF (i.e., the “quasar mode”), remains elusive. From a systematic study of the spectra of ≈24 000 AGN we find that extreme ionised gas kinematics are common, and are most prevalent in radio bright AGN (L1.4 GHz> 103W Hz−1). Follow-up IFU observations have shown that these extreme gas kinematics are extended over kilo-parsec scales. However, the co-existence of high-levels of SF, luminous AGN activity and radio jets raises interesting questions on the primary drivers and impact of these outflows. Galaxy-wide, high-mass outflows are being observed in an increasing number of AGN and are a plausible mechanism for the depletion of gas; however, there is still much work to be done to determine the physical processes that drive these outflows and to measure the level of impact that they have on their host galaxies.
Revealing AGN, young and old stellar populations in HzRGs with PEGASE.3
Authors: Drouart Guillaume , De Breuck Carlos , Vernet Joël , Volmerange Brigitte Rocca , Seymour Nicholas 
Published: July 2014

AbstractThe HeRGÉ (Herschel Radio Galaxy Evolution) project consists of a sample of 70 radio galaxies in the range 1 < z < 5.2. They benefit from continuous coverage from 3 to 870μm with Spitzer, Herschel and sub-mm ground-based instruments (SCUBA, LABOCA). As a calorimeter, IR is an excellent proxy to estimate the contribution of both AGN and starburst, making of radio galaxies perfect candidates to provide new insights into the relationship between AGN and their host galaxies. The IR SED fitting with empirical templates reveals that radio galaxies are luminous and that their black holes and their host galaxies are not growing simultaneously. Extending the SED to optical/near-IR on a subsample of 12 radio galaxies spanning 1 < z < 4 reveal the necessity of three components to reproduce the observations. Making use of the evolutionary code PEGASE.3 and an AGN torus model, we are able to estimate parameters from the AGN torus, the evolved stellar population and the starburst (SB). They reveal that radio galaxies are massive, evolved, forming the bulk of their mass at very high redshift in a short timescale, but experience episodic, strong SB events, often associated with an AGN activity.
AGN Absorption Linked to Host Galaxies
Authors: Juneau Stéphanie 
Published: July 2014

AbstractMultiwavelength identification of AGN is crucial not only to obtain a more complete census, but also to learn about the physical state of the nuclear activity (obscuration, efficiency, etc.). A panchromatic strategy plays an especially important role when the host galaxies are star-forming. Selecting far-Infrared galaxies at 0.3<z<1, and using AGN tracers in the X-ray, optical spectra, mid-infrared, and radio regimes, we found a twice higher AGN fraction than previous studies, thanks to the combined AGN identification methods and in particular the recent Mass-Excitation (MEx) diagnostic diagram. We furthermore find an intriguing relation between AGN X-ray absorption and the specific star formation rate (sSFR) of the host galaxies, indicating a physical link between X-ray absorption and either the gas fraction or the gas geometry in the hosts. These findings have implications for our current understanding of both the AGN unification model and the nature of the black hole-galaxy connection.
The “entropy floor” is porous – remarks on the coexistence of star formation and kinetic AGN feedback
Authors: Tremblay Grant R. 
Published: July 2014

AbstractWe discuss the morphology of star forming clouds and filaments in the central (≲ 50 kpc) regions of 16 low redshift (z<0.3) cool core brightest cluster galaxies (BCGs). The sample spans decades-wide ranges of X-ray mass deposition and star formation rates as well as active galactic nucleus (AGN) mechanical power, encompassing both high and low extremes of the supposed intracluster medium (ICM) cooling and AGN heating feedback cycle. Amid evidence that the gas fueling both star formation and AGN activity has condensed from the hot atmosphere, we present new and archival Hubble Space Telescope (HST) images of far ultraviolet (FUV) continuum emission directly associated with young stars, acting as a calorimeter for the degree to which the suppression of star formation by AGN mechanical feedback may be spatially or temporally inefficient. We discuss evidence for temporal and possibly cyclical variation in star formation rate, wherein elevated cooling episodes are permitted when AGN feedback is in a low-power state, and vice-versa. Several sources exhibit strong morphological evidence that low levels of star formation can survive and may indeed be triggered by the passage of a propagating radio source. We conclude by discussing the apparent coexistence of feedback and star formation. If AGN mechanical power does establish an “entropy floor”, this floor must be porous, or raise and lower as the AGN varies in power.
AGN populations in compact groups of galaxies
Authors: Amirkhanian A. S. , del Olmo A. , Egikian A. G. , Tiersch H. , Stoll D. , Perea J. 
Published: July 2014

AbstractCompact groups of galaxies (CGG) have revealed some interesting problems from their origin and lifetime to the evolution of their members in such dense configurations. Some authors suppose that CGG probably are the best location for AGNs in the local Universe. According to our preliminary data about 7–10% of member galaxies in Shahbazian compact groups (SHCGs) are emission-line galaxies including the broad-line AGN and the narrow emission-line galaxies. Shahbazian 355/4 is a classical Seyfert 1 galaxy at the same redshift as host group. Moreover Shahbazian 278/4 is also a broad-line AGN in an early-type galaxy. This is the first emission-line object in SHCGs. Meanwhile there is no Seyfert 1 galaxy among the spectroscopically investigated galaxies in the South compact groups, although more than 70% of the member galaxies in these groups probably have an active nucleus. The UZC- compact groups have an excess of Seyfert 2s (but not Seyfert 1s!). Further observational studies are necessary to understand such and many other questions related to the puzzle of CGG.
Relative frequencies of supernovae versus properties of spiral hosts
Authors: Hakobyan A. A. , Nazaryan T. A. , Adibekyan V. Zh. , Petrosian A. R. , Aramyan L. S. , Kunth D. , Mamon G. A. , de Lapparent V. , Bertin E. , Gomes J. M. , Turatto M. 
Published: July 2014

AbstractIn this work, we present an analysis of SNe number ratios in spiral galaxies with different morphological subtypes, luminosities, sSFR, and metallicities, to provide important information about the physical properties of the progenitor populations.
The galaxy environment of a QSO at z ~ 5.7
Authors: Bañados E. , Venemans B. P. , Walter Fabian , Kurk Jaron , Overzier Roderik , Ouchi Masami 
Published: July 2014

AbstractHigh-redshift quasars are thought to reside in the most massive halos in the early universe and should therefore be located in fields with overdensities of galaxies, which are expected to evolve into galaxy clusters seen in the local Universe. In Bañados et al. (2013), we used deep narrow-band imaging to study the environment of the z=5.72 quasar ULAS J0203 + 0012. The redshift range probed by our narrow band selection is Δz ~ 0.1. This was the first time that Lyman alpha emitters (LAEs) were searched for near a z ~ 6 quasar, to provide clues on the surroundings of quasars at the end of the epoch of reionization. The main result of this work is that no enhancement of LAEs has been found in the surroundings of ULAS J0203 + 0012. We discuss different explanations and interpretations for this non-detection of a galaxy overdensity.
IGM Heating and AGN activity in Fossil Galaxy Groups
Authors: Miraghaei H. , Khosroshahi H. G. , Klöckner H.-R. , Ponman T. J. , Jetha N. N. , Raychaudhury S. 
Published: July 2014

AbstractFossil galaxy groups are energetically and morphologically ideal environments to study the intergalactic medium (IGM) heating, because their inter-galactic gas is undisturbed due to the lack of recent group scale mergers. We study the role of active galactic nuclei (AGN) in heating the IGM in a sample of five fossil galaxy groups by employing properties at 610 MHz and 1.4 GHz. We find that two of the dominant galaxies in fossil groups, ESO 3060170 and RX J1416.4+2315, are associated with the radio lobes. We evaluate the PdV work of the radio lobes and their corresponding heating power and compare to the X-ray emission loss within cooling radius. Our results show that the power due to mechanical heating is not sufficiently high to suppress the cooling.
Spatially Resolved Spectroscopy to Confirm or Disprove Dual Active Galactic Nuclei
Authors: McGurk Rosalie C. , Max Claire E. , Medling Anne , Shields Gregory A. 
Published: July 2014

AbstractWhen galaxies merge, gas accretes onto both central supermassive black holes. Thus, one expects to see dual active galactic nuclei (AGNs) in a fraction of galaxy mergers. Candidates for galaxies containing dual AGNs have been identified by the presence of double-peaked narrow [O III] emission lines and by high spatial resolution images of close galaxy pairs. 30% of double-peaked narrow [OIII] emission line SDSS AGNs have two spatial components within a 3″ radius. However, spatially resolved spectroscopy is needed to confirm these galaxy pairs as systems with double AGNs. With the Keck 2 Laser Guide Star Adaptive Optics system and the OSIRIS near-infrared integral field spectrograph, we obtained spatially resolved spectra for SDSS J095207.62+255257.2, confirming that it contains a Type 1 and a Type 2 AGN separated by 4.8 kpc (=1.0″). We performed similar integral field and long-slit spectroscopy observations of more spatially separated candidate dual AGNs and will report on the varied results. By assessing what fraction of radio-quiet double-peaked emission line SDSS AGNs are true dual AGNs, we can better constrain the statistics of dual AGNs and characterize physical conditions throughout these interacting AGNs.
When disks collide: major and minor mergers in disk galaxies
Authors: Mezcua M. , Lobanov A. P. , Mediavilla E. , Karouzos M. 
Published: July 2014

AbstractWe present the surface brightness profile fitting of a sample of double nucleus disk galaxies, minor merger candidates. We have decomposed these systems into two compact nuclear components and one or two extended galaxy disk components and estimated the luminosity of the primary and secondary nucleus and of the host galaxy and the separation between the two nuclei. Based on the ratio of nuclear luminosities we find that most of the sources qualify as major mergers despite their initial classification as minor merging systems. This is supported by the finding that 65% of the host galaxies are fitted only by one galaxy disk and that the luminosity of both the primary and the secondary nucleus decreases with decreasing nuclear separation, as expected from simulations of disk galaxy mergers. All these results indicate that these sources are most plausibly in the post-merger state of a major merger event. We also identify 19 candidates to binary active nucleus with nuclear separation ≤1 kpc.
Are the “Physically Bound Systems” beyond the Cosmological Expansion Effect? (A provocative musing on the given theme)
Authors: Harutyunian Haik A. 
Published: July 2014

AbstractInfluence of the dark energy at small scales is considered. Interaction and energy exchange between ordinary matter and dark energy is proposed as a working hypothesis. Some observational facts are put into the base of this consideration: the large rate of lunar retreat and the acceleration of cosmic expansion which proves the energy exchange between ordinary matter and dark energy. If the possibility of the space and matter expansion at the scales under consideration is accepted one can show that the dark energy transformed into the object's potential energy is enough to generate cluster of galaxies over the Hubble time due to matter ejection mechanism.
Optical variability of quasars: a damped random walk
Authors: Ivezić Željko , MacLeod Chelsea 
Published: July 2014

AbstractA damped random walk is a stochastic process, defined by an exponential covariance matrix that behaves as a random walk for short time scales and asymptotically achieves a finite variability amplitude at long time scales. Over the last few years, it has been demonstrated, mostly but not exclusively using SDSS data, that a damped random walk model provides a satisfactory statistical description of observed quasar variability in the optical wavelength range, for rest-frame timescales from 5 days to 2000 days. The best-fit characteristic timescale and asymptotic variability amplitude scale with the luminosity, black hole mass, and rest wavelength, and appear independent of redshift. In addition to providing insights into the physics of quasar variability, the best-fit model parameters can be used to efficiently separate quasars from stars in imaging surveys with adequate long-term multi-epoch data, such as expected from LSST.
Optical microvariability of bright type 2 quasars
Authors: Polednikova Jana , Ederoclite Alessandro , Cepa Jordi , de Diego Onsurbe José Antonio , González-Serrano José Ignacio 
Published: July 2014

AbstractWe present results from a project focused on searching optical microvariabilty (also known as “intra-night” variability) in type 2 - obscured - quasars. Optical microvariability can be described as very small changes in the flux, typically in the order of hundredths of magnitude, which can be observed on timescales of hours. Such studies have been so far conducted for samples of blazars and type 1, unobscured, AGNs, where the optical microvariability was detected with success. We have focused on obscured targets which would pose a challenge to the AGN standard model. In the present work, however, we have observed a sample of three bright (g mag < 17) type 2 quasar, based on the catalog of type 2 quasars from SDSS of Reyes et al. (2008). The observations were carried out with the 1.5 meter telescope at San Pedro Martir observatory in Mexico. The sample was observed during an observation period of four days in Johnsons V filter, resulting in at least two continuous intervals of observations per target during the observational run. We have obtained differential light curves for our sources as well as for the comparison stars. They were analyzed using one-way analysis of variance statistical test (ANOVA), which has been repeatedly used in the past for studies of unobscured targets. Based on the results from the statistical analysis, we show that at least two out of three observed targets appear to be variable on time scales of hours. So far, this is the first study which confirmed existence of optical microvariability in type 2 quasars.
Results on Panoramic Spectroscopy of Mrk 171
Authors: Hakopian S. A. , Balayan S. K. , Movsessian T. A. 
Published: July 2014

AbstractObservations of Mrk 171, aimed at conduction of panoramic spectroscopy, were undertaken with the Byurakan 2.6-m telescope using spectrograph “VAGR”. Within the two components of the galaxy, Mrk171W and Mrk171E, there were differentiated eight condensations of starforming activiity, i.e. HII-regions, and no sign of AGN activity was revealed inspite of existing suggestions.
The MASIV Legacy: Surveying AGN Intra-day Variability at Radio Wavelengths
Authors: Koay J. Y. , Macquart J.-P. , Rickett B. J. , Bignall H. E. , Jauncey D. L. , Pursimo T. , Reynolds C. , Lovell J. E. J. , Kedziora-Chudczer L. , Ojha R. 
Published: July 2014

AbstractThe Micro-arcsecond Scintillation-Induced Variability (MASIV) Survey and its follow-up observations have provided large datasets of AGN intra-day variability (IDV) at radio wavelengths. These data have shown that IDV arises mainly from scintillation caused by scattering in the ionized interstellar medium (ISM) of our Galaxy, based on correlation with Galactic latitudes and line-of-sight Galactic electron column densities. The sensitivity of interstellar scintillation (ISS) towards source angular sizes has provided a new tool for studying the most compact components of radio-loud AGNs at microarcsecond (μas) scale resolution - much higher than any ground-based radio interferometer. We present here key results from the MASIV Survey and its follow-up observations, and point to relevant papers where these results have been published.
The Role of Radio Loud Phase of Nuclear Activity in Galaxy Formation and Evolution
Authors: Ohanian Gabriel A. 
Published: July 2014

AbstractKey questions, which arise when one tries to clear up a problem of formation and evolution of galaxies, is the question of energy: what is the energetic budget of AGN owing to form galaxies and provide its subsequent development? Hence, for understanding the formation and evolution of galaxies, it is important to estimate the energetic budget of AGN which we try to do involving radio loud phase of nuclear activity.
Direct Detection of FoxP3 Expression in Thymic Double-Negative CD4−CD8− Cells by Flow Cytometry
Authors: Liu Gang , Li Zongfang , Wei Yang , Lin Yan , Yang Cengceng , Liu Tie 
Published: July 2014

AbstractFoxp3 expression is a marker of regulatory T cells (Treg), but how early it is expressed in the thymus is still not fully defined. In this study, we examined Foxp3 expression in double-negative (DN) CD4−CD8− T cell precursors in the thymus by flow cytometry. By increasing the number of collected cells from the conventional 104 cells up to more than 106 cells during flow cytometry, we found that DN cells exhibited higher Foxp3 expression than double-positive (DP) CD4+CD8+ and single-positive (SP) CD4+ or CD8+ (SP) T cells. CD44+ expression positively correlated with Foxp3 in thymic DN cells. Furthermore, TCR-β−CD25+ DN cells exhibited the highest frequency of Foxp3-expressing cells. Almost all Foxp3+ cells expressed CD25in DN cells. These results suggest that Foxp3 expression in DN cells can directly be detected by flow cytometry and it was positively corelated with CD25 and CD44 in DN cells.
Hf-Nd isotopic variability in mineral dust from Chinese and Mongolian deserts: implications for sources and dispersal
Authors: Zhao Wancang , Sun Youbin , Balsam William , Lu Huayu , Liu Lianwen , Chen Jun , Ji Junfeng 
Published: July 2014

AbstractMineral dust provenances are closely related to the orogenic processes which may have distinct Hf-Nd isotopic signatures. Here we report the clay-sized (<2 μm) Hf-Nd isotope data from Asian dust sources to better constrain the source and transport dynamics of dust deposition in the North Pacific. Our results show that there is a more positive radiogenic Hf isotopic composition with clay-sized fractions than the corresponding bulk sample and a decoupling of the Hf-Nd couplets in the clay formation during the weathering process. The clay-sized Hf-Nd isotopic compositions of the desert samples from the Sino-Korean-Tarim Craton (SKTC) are different from those of the Gobi and deserts from the Central Asian Orogeny Belt (CAOB) due to varying tectonic and weathering controls. The Hf-Nd isotopic compositions of dust in the North Pacific central province (NPC) match closely with those from the Taklimakan, Badain Jaran and adjacent Tengger deserts, implying that the NPC dust was mainly transported from these potential sources by the westerly jet. Our study indicates that dusts from the CAOB Gobi deserts either didn't arrive in NPC or were quantitatively insignificant, but they were likely transported to the North Pacific margin province (NPM) by East Asian winter monsoon.
Area‐ and power‐efficient DC–DC converter with on‐chip compensation
Authors: Liu Pang‐Jung , Chang Yi‐Hsiang 
Published: July 2014

A dual‐path capacitor multiplier (DPCM) technique is proposed for on‐chip frequency compensation. The DPCM uses two currents to charge and discharge a compensation capacitor concurrently. Consequently, the equivalent capacitance is amplified dramatically with slight increase in silicon area and power. Thanks to the DPCM, the transient response of the DC–DC converter has improved significantly because of the small compensation capacitor. Experimental results demonstrate converter stability and transient response. The transient recovery time of a 450 mA step load change is <30 μs. With the proposed technique, the compensation capacitor is shrunk significantly and adding the compensation resistor would have helped in improving transient response.
Fresnel‐assisted self‐heterodyne detection for Brillouin gain spectrum characterisation in polymer optical fibres
Authors: Mizuno Y. , Hayashi N. , Nakamura K. 
Published: July 2014

It has been experimentally shown that by utilising the Fresnel‐reflected light as the reference light, Brillouin signals in polymer optical fibres (POFs) can be observed with a higher signal‐to‐noise ratio (SNR) than those measured with standard self‐heterodyne detection. This method is basically the same in setup as direct detection, leading to an additional advantage of system simplicity. Moreover, it has been demonstrated that the Brillouin signal in a 1 cm‐long POF can be observed with a moderate SNR using this technique, indicating a potential feasibility of POF‐based distributed Brillouin measurement with a millimetre‐order spatial resolution.
Compact wideband and dual‐band antenna for TD‐LTE and WLAN applications
Authors: Chen Shaojian , Dong Dacheng , Liao Zhouying , Cai Qibo , Liu Gui 
Published: July 2014

A novel compact wideband and dual‐band microstrip‐fed antenna is proposed. By using symmetrical inverted‐L‐shaped strips, a fork‐shaped strip, a rectangular slot and a defected ground plane, the dual‐band resonances of the antenna are generated. The measured impedance bandwidths are 1.12 GHz for the lower frequency band (1.87–2.99 GHz), and 780 MHz for the higher frequency band (5.10–5.88 GHz). The fabricated antenna can be used to cover the entire required bands for time‐division‐long‐term evolution (1880–2655 MHz) and wireless local area network 802.11 a/b/g (2.4–2.4835, 5.15–5.875 GHz). The measured gain at 2.4 and 5.5 GHz is 2.1 and 6.1 dBi, respectively. The antenna shows a compact size of 25 × 30 × 0.8 mm. The details of the antenna design, the operation mechanism and the simulated and measured results are presented.
Electric‐LC resonators at microwave for oil sensing
Authors: Yaghmaee P. , Minoofar H. 
Published: July 2014

A modified electric‐LC resonators array is proposed which makes use of a capacitive gap for oil sensing. The resonator was fabricated on a Duroid 5880 substrate with a thickness of 3.05 mm. The modified resonator operates at a frequency of 6.28 GHz and has an 8 × 2 array of cells. The compared results from the prototype measurements and the fitted curves from full‐wave electromagnetic simulations indicate accurate relative permittivity sensing for this resonator at the C‐band.