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K. Hryniewicz

Other affiliations: University of Białystok
Bio: K. Hryniewicz is an academic researcher from University of Geneva. The author has contributed to research in topics: Quasar & Line (formation). The author has an hindex of 11, co-authored 19 publications receiving 440 citations. Previous affiliations of K. Hryniewicz include University of Białystok.

Papers
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Journal ArticleDOI
TL;DR: In this article, the authors proposed a method based on determination of the size of the Broad Line Region from the emission line delay, determination of absolute monochromatic luminosity either from the observed statistical relation or from a model of the formation of the broad line region, and determination of observed monochrome flux from photometry.
Abstract: High redshift quasars can be used to deduce the distribution of dark energy in the Universe, as a complementary tool to SN Ia. The method is based on determination of the size of the Broad Line Region from the emission line delay, determination of the absolute monochromatic luminosity either from the observed statistical relation or from a model of the formation of the Broad Line Region, and determination of the observed monochromatic flux from photometry. This allows to obtain the luminosity distance to a quasar independently from its redshift. The accuracy of the measurements is however, a key issue. We model the expected accuracy of the measurements by creating artificial quasar monochromatic lightcurves and responses from the Broad Line Region under various assumptions about the variability of a quasar, Broad Line Region extension, distribution of the measurements in time, accuracy of the measurements and the intrinsic line variability. We show that the five year monitoring based on Mg II line should give the accuracy of 0.06 - 0.32 magnitude in the distance modulus which allows to put interesting constraints on the cosmological models. Monitoring of higher redshift quasars based on CIV lines is problematic due to much higher level of the intrinsic variability of CIV in comparison with Mg II.

72 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used the broad line region (BLR) from the emission line delay, the determination of the absolute monochromatic luminosity either from the observed statistical relation or from a model of the formation of the BLR, and the observed monochrome flux from photometry.
Abstract: Context. High-redshift quasars can be used to constrain the equation of state of dark energy. They can serve as a complementary tool to supernovae Type Ia, especially at z > 1.Aims. The method is based on the determination of the size of the broad line region (BLR) from the emission line delay, the determination of the absolute monochromatic luminosity either from the observed statistical relation or from a model of the formation of the BLR, and the determination of the observed monochromatic flux from photometry. This allows the luminosity distance to a quasar to be obtained, independently from its redshift. The accuracy of the measurements is, however, a key issue.Methods. We modeled the expected accuracy of the measurements by creating artificial quasar monochromatic lightcurves and responses from the BLR under various assumptions about the variability of a quasar, BLR extension, distribution of the measurements in time, accuracy of the measurements, and the intrinsic line variability.Results. We show that the five-year monitoring of a single quasar based on the Mg II line should give an accuracy of 0.06−0.32 mag in the distance modulus which will allow new constraints to be put on the expansion rate of the Universe at high redshifts. Successful monitoring of higher redshift quasars based on C IV lines requires proper selection of the objects to avoid sources with much higher levels of the intrinsic variability of C IV compared to Mg II.

70 citations

Journal ArticleDOI
TL;DR: Weak emission line quasars are a rare and puzzling group of objects as discussed by the authors, and their line properties are not consistent with the trends expected at high accretion rates, which may indicate that the quasar active phase consists of several sub-phases, each starting with a fresh build-up of the Broad Line Region.
Abstract: Weak emission line quasars are a rare and puzzling group of objects. In this paper we present one more object of this class found in the Sloan Digital Sky Survey (SDSS). The quasar SDSS J094533.99+100950.1, lying at z = 1.66, has practically no CIV emission line, a red continuum very similar to the second steepest of the quasar composite spectra of Richards et al., is not strongly affected by absorption and the MgII line, although relatively weak, is strong enough to measure the black hole mass. The Eddington ratio in this object is about 0.45, and the line properties are not consistent with the trends expected at high accretion rates. We propose that the most probable explanation of the line properties in this object, and perhaps in all weak emission line quasars, is that the quasar activity has just started. A disk wind is freshly launched so the low ionization lines which form close to the disk surface are already observed but the wind has not yet reached the regions where high ionization lines or narrow line components are formed. The relatively high occurrence of such a phenomenon may additionally indicate that the quasar active phase consists of several sub-phases, each starting with a fresh build-up of the Broad Line Region.

60 citations

Journal ArticleDOI
TL;DR: In this article, a simple physical mechanism was proposed for the formation of the Low Ionization Line part of the Broad Line Region in Active Galactic Nuclei, where the local effective temperature of a non-illuminated accretion disk drops below 1000 K and allows for dust formation.

51 citations

Journal ArticleDOI
TL;DR: In this article, the authors measured the black hole mass in a very special object, RE J1034+396, one of the two AGNs with QPO oscillations detected in X-rays, and a single bright AGN with optical band totally dominated by starlight.
Abstract: The black hole mass measurement in active galaxies is a challenge, particularly in sources where the reverberation method cannot be applied. We aim to determine the black hole mass in a very special object, RE J1034+396, one of the two AGN with QPO oscillations detected in X-rays, and a single bright AGN with optical band totally dominated by starlight. We fit the stellar content using the code starlight, and the broad band disk contribution to optical/UV/X-ray emission is modeled with optxagnf. We also determine the black hole mass using several other independent methods. Various methods give contradictory results. Most measurements of the blacc hole mass are in the range 1.e6-1.e7 Msun, and the measurements based on dynamics give higher values than measurements based on Hbeta and Mg II emission lines.

39 citations


Cited by
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01 Jan 1965
TL;DR: In this article, Maarten Schmidt solved the puzzle by recognizing the Balmer lines of hydrogen, strongly redshifted, in the spectrum of the quasar 3C 273, and reached the "most direct and least objectionable" conclusion, that 3c 273 was no star, but the enormously bright nucleus of a distant galaxy.
Abstract: In the early 1960s, astronomers were puzzled by quasars — sources of intense radio emission that seemed to be stars, but had unintelligible optical spectra. In 1963, Maarten Schmidt solved the puzzle by recognizing the Balmer lines of hydrogen, strongly redshifted, in the spectrum of the quasar 3C 273. Schmidt reached the "most direct and least objectionable" conclusion, that 3C 273 was no star, but the enormously bright nucleus of a distant galaxy.

505 citations

Journal ArticleDOI
TL;DR: A detailed view of the possible detection of a black hole can be found in this article, where the authors show a schematic view of a path leading to this objective from observations of existing type.
Abstract: Since the observational detection of black holes is inherently difficult, it is important to begin with a clear idea of the general possibilities for such detection as they seem practical from observations of existing type. FIGURE 1 shows a schematic view of the paths leading to this objective. The primary attribute by which we hope to recognize a black hole is its gravitational mass, which is discernible through its effect on macroscopic bodies (orbital motions) or microscopic bodies (compressional heating with emission of x-rays). The combination of large mass, small radius, and small luminosity constitutes the unique signature of a massive black hole, and there do exist invisible components to numerous binaries that may fulfill these conditions. Since other small objects (white dwarfs and neutrons stars) cannot have masses exceeding about 1.5 Mo, large mass means M 2 2 Mo. The notions of small radius and small luminosity can be taken in general to mean that these quantities are small compared with the values expected for any conceivable stable astronomical body that could be present. Those binaries for which fairly serious black hole arguments have been made to date are e Aur,\"34,10 p Lyrae,3,\" Cygnus X1 = HDE 226868,',e and BM Ori.\" Space does not permit discussion of the merits of these cases, although counterarguments have been made regarding ,8 Lyrae',* and might well be made against Cyg X-1 and BM Ori. It has been predicted for most of a decade, if not longer, that black holes in binary systems might be x-ray sources. Indeed, Cygnus X-1 may be one such case. However, x-rays are not the only evidence that might uncover collapsed stars, and it is fortunate that this is so because of the intrinsic difficulty of unambiguous identification of a black hole. That is, we would like, if at all possible, to have several independent demonstrations that a black hole is present. A possible path is offered by spectroscopic and photometric observations of certain unusual binaries that have long histories of observational peculiarities and, in addition, have massive invisible secondary components. It would be quite convincing if we could travel both paths of FIGURE 1 for some particular binary system. For example, E Aur might turn on as an x-ray source, or Cyg X-1 might, on detailed examination, show properties similar to those of BM Ori. An appreciation for the left path of FIGURE 1 (optical observations) may be gained through consideration of the eclipsing binary E Aurigae. The most striking peculiarity of e Aur is that the eclipse is apparently total (flat bottom)-yet the spectrum of the eclipsed component remains visible at all times. This, of course, proves that the eclipse really is not total, so we must find another explanation. It can easily be shown' that the eclipse also is not annular and that the disk models by Huang,' by Kopal,5 and by Cameron' are not compatible with the observations.'\" Useful observations of E Aur have been made since 1848, and models for the eclipse mechanism have been offered over the past 40 years. To explain

479 citations

Journal ArticleDOI
TL;DR: In this paper, a review of recent progress in high-contrast imaging with particular emphasis on observational results, discoveries near and below the deuterium-burning limit, and a practical overview of large-scale surveys and dedicated instruments is presented.
Abstract: High-contrast adaptive optics imaging is a powerful technique to probe the architectures of planetary systems from the outside-in and survey the atmospheres of self-luminous giant planets. Direct imaging has rapidly matured over the past decade and especially the last few years with the advent of high-order adaptive optics systems, dedicated planet-finding instruments with specialized coronagraphs, and innovative observing and post-processing strategies to suppress speckle noise. This review summarizes recent progress in high-contrast imaging with particular emphasis on observational results, discoveries near and below the deuterium-burning limit, and a practical overview of large-scale surveys and dedicated instruments. I conclude with a statistical meta-analysis of deep imaging surveys in the literature. Based on observations of 384 unique and single young ($\approx$5--300~Myr) stars spanning stellar masses between 0.1--3.0~\Msun, the overall occurrence rate of 5--13~\Mjup \ companions at orbital distances of 30--300~AU is 0.6$^{+0.7}_{-0.5}$\% assuming hot-start evolutionary models. The most massive giant planets regularly accessible to direct imaging are about as rare as hot Jupiters are around Sun-like stars. Dividing this sample into individual stellar mass bins does not reveal any statistically-significant trend in planet frequency with host mass: giant planets are found around 2.8$^{+3.7}_{-2.3}$\% of BA stars, $<$4.1\% of FGK stars, and $<$3.9\% of M dwarfs. Looking forward, extreme adaptive optics systems and the next generation of ground- and space-based telescopes with smaller inner working angles and deeper detection limits will increase the pace of discovery to ultimately map the demographics, composition, evolution, and origin of planets spanning a broad range of masses and ages.

397 citations

Book
26 May 2015
TL;DR: Dodelson et al. as discussed by the authors showed that the universe is so much bigger than the bit we can see in our observable bubble and we know nothing about what lies out there in the cosmos.
Abstract: The universe is so much bigger than the bit we can see in our observable bubble and we know nothing about what lies out there in the cosmos. The challenge is so much bigger than is shown on this chart and it is evident that we really only understand a tiny fraction of the whole cosmos. Theories ​for Dark Energy have been around for a long time but we still have no satisfactory explanation. None of the theories are adequate, some are clearly wrong – an error of 10^120 is a really big miss! Scott Dodelson of Carnegie Mellon University, one of the lead scientists behind the Dark Energy Survey’s new map of cosmic structure says:

384 citations

Journal ArticleDOI
TL;DR: In this article, a review of recent progress in high-contrast imaging with particular emphasis on observational results, discoveries near and below the deuterium-burning limit, and a practical overview of large-scale surveys and dedicated instruments is presented.
Abstract: High-contrast adaptive optics imaging is a powerful technique to probe the architectures of planetary systems from the outside-in and survey the atmospheres of self-luminous giant planets. Direct imaging has rapidly matured over the past decade and especially the last few years with the advent of high-order adaptive optics systems, dedicated planet-finding instruments with specialized coronagraphs, and innovative observing and post-processing strategies to suppress speckle noise. This review summarizes recent progress in high-contrast imaging with particular emphasis on observational results, discoveries near and below the deuterium-burning limit, and a practical overview of large-scale surveys and dedicated instruments. I conclude with a statistical meta-analysis of deep imaging surveys in the literature. Based on observations of 384 unique and single young ($\approx$5--300~Myr) stars spanning stellar masses between 0.1--3.0~\Msun, the overall occurrence rate of 5--13~\Mjup \ companions at orbital distances of 30--300~AU is 0.6$^{+0.7}_{-0.5}$\% assuming hot-start evolutionary models. The most massive giant planets regularly accessible to direct imaging are about as rare as hot Jupiters are around Sun-like stars. Dividing this sample into individual stellar mass bins does not reveal any statistically-significant trend in planet frequency with host mass: giant planets are found around 2.8$^{+3.7}_{-2.3}$\% of BA stars, $<$4.1\% of FGK stars, and $<$3.9\% of M dwarfs. Looking forward, extreme adaptive optics systems and the next generation of ground- and space-based telescopes with smaller inner working angles and deeper detection limits will increase the pace of discovery to ultimately map the demographics, composition, evolution, and origin of planets spanning a broad range of masses and ages.

261 citations