John Timlin
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View article: The Nature of Luminous Quasars with Very Large C iv Equivalent Widths
The Nature of Luminous Quasars with Very Large C iv Equivalent Widths Open
We report results for a complete sample of 10 luminous radio-quiet quasars with large C iv equivalent widths (EW ≥ 150 Å). For 8/10 we performed Chandra snapshot observations. We find that, in addition to the enhanced C iv line EW, their H…
View article: Incorporating Measurement Error in Astronomical Object Classification
Incorporating Measurement Error in Astronomical Object Classification Open
Most general-purpose classification methods, such as support-vector machine (SVM) and random forest (RF), fail to account for an unusual characteristic of astronomical data: known measurement error uncertainties. In astronomical data, this…
View article: Sensitive <i>Chandra</i> coverage of a representative sample of weak-line quasars: revealing the full range of X-ray properties
Sensitive <i>Chandra</i> coverage of a representative sample of weak-line quasars: revealing the full range of X-ray properties Open
We present deeper Chandra observations for weak-line quasars (WLQs) in a representative sample that previously had limited X-ray constraints, and perform X-ray photometric analyses to reveal the full range of X-ray properties of WLQs. Only…
View article: The XMM-SERVS Survey: XMM-Newton Point-source Catalogs for the W-CDF-S and ELAIS-S1 Fields
The XMM-SERVS Survey: XMM-Newton Point-source Catalogs for the W-CDF-S and ELAIS-S1 Fields Open
We present the X-ray point-source catalogs in two of the XMM-Spitzer Extragalactic Representative Volume Survey (XMM-SERVS) fields, W-CDF-S (4.6 deg 2 ) and ELAIS-S1 (3.2 deg 2 ), aiming to fill the gap between deep pencil-beam X-ray surve…
View article: The X-ray spectral and variability properties of typical radio-loud quasars
The X-ray spectral and variability properties of typical radio-loud quasars Open
We present X-ray spectral and long-term variability analyses of an unbiased sample of 361 optically selected radio-loud quasars (RLQs) utilizing sensitive serendipitous X-ray data from the Chandra and XMM-Newton archives. The spectral and …
View article: The aox--HeII EW Connection in Radio-Loud Quasars
The aox--HeII EW Connection in Radio-Loud Quasars Open
Radio-loud quasars (RLQs) are known to produce excess X-ray emission, compared to radio-quiet quasars (RQQs) of the same luminosity, commonly attributed to jet-related emission. Recently, we found that the HeII EW and $α_{\rm{ox}}$ in RQQs…
View article: What controls the UV-to-X-ray continuum shape in quasars?
What controls the UV-to-X-ray continuum shape in quasars? Open
We present an investigation of the interdependence of the optical-to-X-ray spectral slope (αox), the He ii equivalent-width (EW), and the monochromatic luminosity at 2500 Å (L2500). The values of αox and He ii EW are indicators of the stre…
View article: The aox--HeII EW Connection in Radio-Loud Quasars
The aox--HeII EW Connection in Radio-Loud Quasars Open
The catalog and research note presenting the X-ray and HeII EW properties of Radio-loud quasars. Our results indicate that the X-ray emission from typical RLQs largely originates in the corona and not from a jet-linked component.
View article: The aox--HeII EW Connection in Radio-Loud Quasars
The aox--HeII EW Connection in Radio-Loud Quasars Open
The catalog and research note presenting the X-ray and HeII EW properties of Radio-loud quasars. Our results indicate that the X-ray emission from typical RLQs largely originates in the corona and not from a jet-linked component.
View article: The α <sub>ox</sub>–He ii EW Connection in Radio-loud Quasars
The α <sub>ox</sub>–He ii EW Connection in Radio-loud Quasars Open
Radio-loud quasars (RLQs) are known to produce excess X-ray emission, compared to radio-quiet quasars (RQQs) of the same luminosity, commonly attributed to jet-related emission. Recently, we found that the He ii EW and α ox in RQQs are str…
View article: Long-Timlescale X-ray Variability of BAL and Mini-BAL Quasars
Long-Timlescale X-ray Variability of BAL and Mini-BAL Quasars Open
We investigated the rest-frame $\approx$0.1-5 year X-ray variability properties of an unbiased and uniformly selected sample of 24 BAL and 35 mini-BAL quasars, making it the largest representative sample used to investigate such variabilit…
View article: Long Timescale X-ray Variability of BAL and mini-BAL quasars
Long Timescale X-ray Variability of BAL and mini-BAL quasars Open
Serendipitous and targeted Chandra observations of BAL and mini-BAL quasars identified in SDSS DR16Q. This data set contains 293 observations of 93 BAL and mini-BAL quasars. This data accompanies the research note: Timlin, J., Brandt, W.N.…
View article: Long Timescale X-ray Variability of BAL and mini-BAL quasars
Long Timescale X-ray Variability of BAL and mini-BAL quasars Open
Serendipitous and targeted Chandra observations of BAL and mini-BAL quasars identified in SDSS DR16Q. This data set contains 293 observations of 93 BAL and mini-BAL quasars. This data accompanies the research note: Timlin, J., Brandt, W.N.…
View article: Long Timescale X-ray Variability of BAL and mini-BAL quasars
Long Timescale X-ray Variability of BAL and mini-BAL quasars Open
Serendipitous and targeted Chandra observations of BAL and mini-BAL quasars identified in SDSS DR16Q. This data set contains 293 observations of 93 BAL and mini-BAL quasars. This data accompanies the research note: Timlin, J., Brandt, W.N.…
View article: The frequency of extreme X-ray variability for radio-quiet quasars
The frequency of extreme X-ray variability for radio-quiet quasars Open
We analyse 1598 serendipitous Chandra X-ray observations of 462 radio-quiet quasars to constrain the frequency of extreme amplitude X-ray variability that is intrinsic to the quasar corona and innermost accretion flow. The quasars in this …
View article: On the Fraction of X-ray Weak Quasars from the Sloan Digital Sky Survey
On the Fraction of X-ray Weak Quasars from the Sloan Digital Sky Survey Open
We investigate systematically the X-ray emission from type 1 quasars using a sample of 1825 Sloan Digital Sky Survey (SDSS) non-broad absorption line (non-BAL) quasars with Chandra archival observations. A significant correlation is found …
View article: Spectroscopy of Broad Absorption Line Quasars at 3 ≲ Z ≲ 5. I. Evidence for Quasar Winds Shaping Broad/Narrow Emission Line Regions
Spectroscopy of Broad Absorption Line Quasars at 3 ≲ Z ≲ 5. I. Evidence for Quasar Winds Shaping Broad/Narrow Emission Line Regions Open
We present an observational study of 22 broad absorption line quasars (BAL QSOs) at based on optical/near-IR spectroscopy, aiming to investigate quasar winds and their effects. The near-IR spectroscopy covers the H β and/or Mg ii broad emi…
View article: The correlations between optical/UV broad lines and X-ray emission for a large sample of quasars
The correlations between optical/UV broad lines and X-ray emission for a large sample of quasars Open
We present Chandra observations of 2106 radio-quiet quasars in the redshift range 1.7 ≤ z ≤ 2.7 from the Sloan Digital Sky Survey (SDSS), through data release 14 (DR14), that do not contain broad absorption lines in their rest-frame ultrav…
View article: Deep Hyper Suprime-Cam Images and a Forced Photometry Catalog in W-CDF-S
Deep Hyper Suprime-Cam Images and a Forced Photometry Catalog in W-CDF-S Open
The Wide Chandra Deep Field-South (W-CDF-S) field is one of the SERVS fields with extensive multiwavelength datasets, which can provide insights into the nature and properties of objects in this field. However, the public optical data from…
View article: Deep Hyper Suprime-Cam Images and a Forced Photometry Catalog in W-CDF-S
Deep Hyper Suprime-Cam Images and a Forced Photometry Catalog in W-CDF-S Open
These are the data products associated with the Ni et al. (2018) research note: "Deep Hyper Suprime-Cam Images and a Forced Photometry Catalog in W-CDF-S", Ni Q., Timlin J., Brandt W.N., Yang G., 2018, RNAAS, in press.
View article: Deep Hyper Suprime-Cam Images and a Forced Photometry Catalog in W-CDF-S
Deep Hyper Suprime-Cam Images and a Forced Photometry Catalog in W-CDF-S Open
These are the data products associated with the Ni et al. (2018) research note: "Deep Hyper Suprime-Cam Images and a Forced Photometry Catalog in W-CDF-S", Ni Q., Timlin J., Brandt W.N., Yang G., 2018, RNAAS, in press.
View article: Active Galaxy Science in the LSST Deep-Drilling Fields: Footprints, Cadence Requirements, and Total-Depth Requirements
Active Galaxy Science in the LSST Deep-Drilling Fields: Footprints, Cadence Requirements, and Total-Depth Requirements Open
This white paper specifies the footprints, cadence requirements, and total-depth requirements needed to allow the most-successful AGN studies in the four currently selected LSST Deep-Drilling Fields (DDFs): ELAIS-S1, XMM-LSS, CDF-S, and CO…
View article: The Clustering of High-redshift (2.9 ≤ z ≤ 5.1) Quasars in SDSS Stripe 82
The Clustering of High-redshift (2.9 ≤ z ≤ 5.1) Quasars in SDSS Stripe 82 Open
We present a measurement of the two-point autocorrelation function of photometrically selected high- z quasars over ∼100 deg 2 on the Sloan Digital Sky Survey Stripe 82 field. Selection is performed using three machine-learning algorithms …
View article: Clustering of high-redshift quasars
Clustering of high-redshift quasars Open
In this work, we investigate the clustering of faint quasars in the early Universe and use the clustering strength to gain a better understanding of quasar feedback mechanisms and the growth of central supermassive black holes at early tim…
View article: AGN Populations in Large-volume X-Ray Surveys: Photometric Redshifts and Population Types Found in the Stripe 82X Survey
AGN Populations in Large-volume X-Ray Surveys: Photometric Redshifts and Population Types Found in the Stripe 82X Survey Open
Multiwavelength surveys covering large sky volumes are necessary to obtain an accurate census of rare objects such as high-luminosity and/or high-redshift active galactic nuclei (AGNs). Stripe 82X is a 31.3 X-ray survey with Chandra and XM…
View article: SpIES: THE SPITZER IRAC EQUATORIAL SURVEY
SpIES: THE SPITZER IRAC EQUATORIAL SURVEY Open
We describe the first data release from the Spitzer -IRAC Equatorial Survey (SpIES); a large-area survey of ∼115 deg 2 in the Equatorial SDSS Stripe 82 field using Spitzer during its “warm” mission phase. SpIES was designed to probe suffic…
View article: SpIES: the Spitzer IRAC Equatorial Survey
SpIES: the Spitzer IRAC Equatorial Survey Open
We describe the first data release from the Spitzer-IRAC Equatorial Survey (SpIES); a large-area survey of 115 deg^2 in the Equatorial SDSS Stripe 82 field using Spitzer during its 'warm' mission phase. SpIES was designed to probe sufficie…