Statistical methods for astronomical data with upper limits. I - Univariate distributions

Feigelson, E. D.; Nelson, Paul I.

doi:10.1086/163225

Cited by 677 publications

(714 citation statements)

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“…The value of W does not change significantly between halo masses of -10 11 13  M for the entire sample. 18 The test was performed on our censored data using the astronomy survival analysis code ASURV (Feigelson & Nelson 1985). ASURV is capable of handling single-and double-censored data.…”

Section: Discussionmentioning

confidence: 99%

“…The distribution can be fit as a exponential with a scale-length of 1.1R vir , i.e., Å = , where the normalization factor, A, is equal to 0.9 Å. The fit was derived using the Buckley-James 17 method (Buckley & James 1979) and Expectation-maximization algorithm as implemented in the survival analysis software package, ASURV (Feigelson & Nelson 1985). The equivalent width data presented here are the same as that of Figure2 of Borthakur et al (2015), however, the abscissa is different, because we have adopted the Kravtsov et al (2014), Liang & Chen (2014) formalism with modifications based on the findings of Mandelbaum et al (2016) for halo masses and virial radii.…”

Section: Structurementioning

confidence: 99%

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The Properties of the Circumgalactic Medium in Red and Blue Galaxies: Results From the Cos-Gass+cos-Halos Surveys

Borthakur

Heckman

Tumlinson

et al. 2016

ApJ

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We use the combined data from the COS-GASS and COS-Halos surveys to characterize the Circum-Galactic Medium (CGM) surrounding typical low-redshift galaxies in the mass range  *~-M M 10 9.5 11.5, and over a range of impact parameters extending to just beyond the halo virial radius (R vir ). We find the radial scale length of the distributions of the equivalent widths of the Lyαand Si III absorbers to be ∼1 and ∼0.4R vir , respectively. The radial distribution of equivalent widths is relatively uniform for the blue galaxies, but highly patchy (i.e., it has a low covering fraction) for the red galaxies. We also find that the Lyαand Si III equivalent widths show significant positive correlations with the specific star formation rate (sSFR) of the galaxy. We find a surprising lack of correlations between the halo mass (virial velocity) and either the velocity dispersions or velocity offsets of the Lyαlines. The ratio of the velocity offset to the velocity dispersion for the Lyαabsorbers has a mean value of ∼4, suggesting that a given line of sight is intersecting a dynamically coherent structure in the CGM, rather than a sea of orbiting clouds. The kinematic properties of the CGM are similar in the blue and red galaxies, although we find that a significantly larger fraction of the blue galaxies have large Lyαvelocity offsets (>200 km s −1 ). We show that-if the CGM clouds represent future fuel for star formation-our new results could imply a large drop in the sSFR across the galaxy mass-range we probe.

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Section: Discussionmentioning

confidence: 99%

Section: Structurementioning

confidence: 99%

The Properties of the Circumgalactic Medium in Red and Blue Galaxies: Results From the Cos-Gass+cos-Halos Surveys

Borthakur

Heckman

Tumlinson

et al. 2016

ApJ

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“…In order to account for the upper limits in our sample, we also use statistical methods that are often generalizations of these classical non-parametric test. We use the astronomical survival analysis package (ASURV; Feigelson & Nelson 1985). Using three different tests, the Gehans Generalized Wilcoxon test; the log-rank test; and the Peto and Peto Generalized Wilcoxon test, the difference in the RLs and RLQs distributions of the FIR luminosity is confirmed at > 98.9, > 99.3, and > 98.9 per cent confidence level, respectively.…”

Section: Fir-radio Correlationmentioning

confidence: 99%

Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power

Kalfountzou

Stevens

Jarvis

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Several studies support the existence of a link between the AGN and star formation activity. Radio jets have been argued to be an ideal mechanism for direct interaction between the AGN and the host galaxy. A drawback of previous surveys of AGN is that they are fundamentally limited by the degeneracy between redshift and luminosity in flux-density limited samples. To overcome this limitation, we present far-infrared Herschel observations of 74 radio-loud quasars (RLQs), 72 radio-quiet quasars (RQQs) and 27 radio galaxies (RGs), selected at 0.9 < z < 1.1 which span over two decades in optical luminosity. By decoupling luminosity from evolutionary effects, we investigate how the star formation rate (SFR) depends on AGN luminosity, radio-loudness and orientation. We find that: 1) the SFR shows a weak correlation with the bolometric luminosity for all AGN sub-samples, 2) the RLQs show a SFR excess of about a factor of 1.4 compared to the RQQs, matched in terms of black hole mass and bolometric luminosity, suggesting that either positive radio-jet feedback or radio AGN triggering are linked to star-formation triggering and 3) RGs have lower SFRs by a factor of 2.5 than the RLQ sub-sample with the same BH mass and bolometric luminosity. We suggest that there is some jet power threshold at which radio-jet feedback switches from enhancing star formation (by compressing gas) to suppressing it (by ejecting gas). This threshold depends on both galaxy mass and jet power.

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“…We have tested the statistical significance of the correlation using the computer package ASURV Rev 1.2, developed by Isobe, La Valley & Feigelson (La Valley et al 1992), which implements the methods presented in Feigelson & Nelson (1985) and in Isobe et al (1986). For sources with S (1.4 GHz) ≥ 80 mJy the test by Cox proportional hazard model yields a global χ 2 , with one degree of freedom, of 573 for flat-spectrum and of 800 for steep-spectrum sources.…”

Section: Polarization Properties Of Extragalactic Radio Sourcesmentioning

confidence: 99%

Polarization properties of extragalactic radio sources and their contribution to microwave polarization fluctuations

Mesa

Baccigalupi

Zotti

et al. 2002

A&A

103

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Abstract. We investigate the statistical properties of the polarized emission of extragalactic radio sources and estimate their contribution to the power spectrum of polarization fluctuations in the microwave region. The basic ingredients of our analysis are the NVSS polarization data, the multifrequency study of polarization properties of the B3-VLA sample (Mack et al. 2002) which has allowed us to quantify Faraday depolarization effects, and the 15 GHz survey by Taylor et al. (2001), which has provided strong constraints on the high-frequency spectral indices of sources. The polarization degree of both steep-and flatspectrum sources at 1.4 GHz is found to be anti-correlated with the flux density. The median polarization degree at 1.4 GHz of both steep-and flat-spectrum sources brighter than S (1.4 GHz) = 80 mJy is 2.2%. The data by Mack et al. (2002) indicate a substantial mean Faraday depolarization at 1.4 GHz for steep spectrum sources, while the depolarization is undetermined for most flat/inverted-spectrum sources. Exploiting this complex of information we have estimated the power spectrum of polarization fluctuations due to extragalactic radio sources at microwave frequencies. We confirm that extragalactic sources are expected to be the main contaminant of Cosmic Microwave Background (CMB) polarization maps on small angular scales. At frequencies <30 GHz the amplitude of their power spectrum is expected to be comparable to that of the E-mode of the CMB. At higher frequencies, however, the CMB dominates.

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Statistical methods for astronomical data with upper limits. I - Univariate distributions

Cited by 677 publications

References 0 publications

The Properties of the Circumgalactic Medium in Red and Blue Galaxies: Results From the Cos-Gass+cos-Halos Surveys

The Properties of the Circumgalactic Medium in Red and Blue Galaxies: Results From the Cos-Gass+cos-Halos Surveys

Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power

Polarization properties of extragalactic radio sources and their contribution to microwave polarization fluctuations

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