The DOI matches its Crossref record; 49 of the 49 references it cites were found in a registry or an index.
THE DISCOVERY OF THE FIRST “CHANGING LOOK” QUASAR: NEW INSIGHTS INTO THE PHYSICS AND PHENOMENOLOGY OF ACTIVE GALACTIC NUCLEI
Open accessAbstract
SDSS J015957.64+003310.5 is an X-ray selected, z = 0.31 active galactic nucleus (AGN) from the Stripe 82X survey that transitioned from a Type 1 quasar to a Type 1.9 AGN between 2000 and 2010. This is the most distant AGN, and first quasar, yet observed to have undergone such a dramatic change. We re-observed the source with the double spectrograph on the Palomar 5 m telescope in 2014 July and found that the spectrum is unchanged since 2010. From fitting the optical spectra, we find that the AGN flux dropped by a factor of 6 between 2000 and 2010 while the broad H α emission faded and broadened. Serendipitous X-ray observations caught the source in both the bright and dim state, showing a similar 2–10 keV flux diminution as the optical while lacking signatures of obscuration. The optical and X-ray changes coincide with g -band magnitude variations over multiple epochs of Stripe 82 observations. We demonstrate that variable absorption, as might be expected from the simplest AGN unification paradigm, does not explain the observed photometric or spectral properties. We interpret the changing state of J0159+0033 to be caused by dimming of the AGN continuum, reducing the supply of ionizing photons available to excite gas in the immediate vicinity around the black hole. J0159+0033 provides insight into the intermittency of black hole growth in quasars, as well as an unprecedented opportunity to study quasar physics (in the bright state) and the host galaxy (in the dim state), which has been impossible to do in a single sources until now.
Overview
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Verification
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Citations
Cites
The relationship between infrared, optical, and ultraviolet extinction
Cardelli, J. A., Clayton, G. C., & Mathis, J. S. (1989) · The Astrophysical Journal · doi:10.1086/167900 · Cited by 11,795
Unified Schemes for Radio-Loud Active Galactic Nuclei
Urry, C. M., & Padovani, P. (1995) · Publications of the Astronomical Society of the Pacific · doi:10.1086/133630 · Cited by 4,868
Self-citationUnified Models for Active Galactic Nuclei and Quasars
Antonucci, R. (1993) · Annual Review of Astronomy and Astrophysics · doi:10.1146/annurev.aa.31.090193.002353 · Cited by 3,943
Sloan Digital Sky Survey: Early Data Release
Stoughton, C., Lupton, R. H., Bernardi, M., Blanton, M. R., Burles, S., Castander, F. J., Connolly, A. J., Eisenstein, D. J., Frieman, J. A., Hennessy, G. S., et al. (2002) · The Astronomical Journal · doi:10.1086/324741 · Cited by 2,390
Self-citationEisenstein, D. J., Weinberg, D. H., Agol, E., Aihara, H., Allende Prieto, C., Anderson, S. F., Arns, J. A., Aubourg, É., Bailey, S., Balbinot, E., et al. (2011) · The Astronomical Journal · doi:10.1088/0004-6256/142/3/72 · Cited by 2,179
Self-citationTHE BARYON OSCILLATION SPECTROSCOPIC SURVEY OF SDSS-III
Dawson, K. S., Schlegel, D. J., Ahn, C. P., Anderson, S. F., Aubourg, É., Bailey, S., Barkhouser, R. H., Bautista, J. E., Beifiori, A., Berlind, A. A., et al. (2013) · The Astronomical Journal · doi:10.1088/0004-6256/145/1/10 · Cited by 2,051
Self-citationShappee, B. J., Prieto, J. L., Grupe, D., Kochanek, C. S., Stanek, K. Z., De Rosa, G., Mathur, S., Zu, Y., Peterson, B. M., Pogge, R. W., et al. (2014) · The Astrophysical Journal · doi:10.1088/0004-637x/788/1/48 · Cited by 1,887
The emission-line properties of low-redshift quasi-stellar objects
Boroson, T. A., & Green, R. F. (1992) · The Astrophysical Journal Supplement Series · doi:10.1086/191661 · Cited by 1,585
Vestergaard, M., & Peterson, B. M. (2006) · The Astrophysical Journal · doi:10.1086/500572 · Cited by 1,287
Spectral Energy Distributions and Multiwavelength Selection of Type 1 Quasars
Richards, G. T., Lacy, M., Storrie‐Lombardi, L. J., Hall, P. B., Gallagher, S. C., Hines, D. C., Fan, X., Papovich, C., Vanden Berk, D. E., Trammell, G. B., et al. (2006) · The Astrophysical Journal Supplement Series · doi:10.1086/506525 · Cited by 1,220
Self-citation
Cited by
Alam, S., Aubert, M., Avila, S., Balland, C., Bautista, J. E., Bershady, M. A., Bizyaev, D., Blanton, M. R., Bolton, A. S., Bovy, J., et al. (2021) · Physical Review D · doi:10.1103/physrevd.103.083533 · Cited by 1,337
Self-citationA systematic search for changing-look quasars in SDSS
MacLeod, C. L., Ross, N. P., Lawrence, A., Goad, M., Horne, K., Burgett, W., Chambers, K. C., Flewelling, H., Hodapp, K., Kaiser, N., et al. (2016) · Monthly Notices of the Royal Astronomical Society · doi:10.1093/mnras/stv2997 · Cited by 323
Sánchez-Sáez, P., Lira, H., Martí, L., Sánchez-Pi, N., Arredondo, J., Bauer, F. E., Bayo, A., Cabrera-Vives, G., Donoso-Oliva, C., Estévez, P. A., et al. (2021) · The Astronomical Journal · doi:10.3847/1538-3881/ac1426 · Cited by 47
What drives the growth of black holes: A decade of progress
Alexander, D. M., Hickox, R. C., Aird, J., Combes, F., Costa, T., Habouzit, M., Harrison, C. M., Leng, R. I., Morabito, L. K., Uckelman, S. L., et al. (2025) · New Astronomy Reviews · doi:10.1016/j.newar.2025.101733 · Cited by 18
Metadata
- Authors
- LaMassa, S. M., Cales, S., Moran, E. C., Myers, A. D., Richards, G. T., Eracleous, M., Heckman, T. M., Gallo, L., & Urry, C. M.
- Venue
- The Astrophysical Journal
- Publisher
- American Astronomical Society
- Published
- 2015-02-20
- Volume
- 800
- Issue
- 2
- Pages
- 144
- ISSN
- 0004-637X (ISSN-L)
- 1538-4357
- OpenAlex
- W1698916124
- Cited by
- 451
- References
- 49
- FWCI
- 20.45
- Type
- journal article
- Language
- en
- Open access
- bronze
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
How to cite
Cite CoChat for the checks on this page, and the paper for its own findings.
- This page
- CoChat. (2026). Citation check: THE DISCOVERY OF THE FIRST “CHANGING LOOK” QUASAR: NEW INSIGHTS INTO THE PHYSICS AND PHENOMENOLOGY OF ACTIVE GALACTIC NUCLEI. https://app.cochat.ai/papers/10.1088/0004-637x/800/2/144
- The paper
- LaMassa, S. M., Cales, S., Moran, E. C., Myers, A. D., Richards, G. T., Eracleous, M., Heckman, T. M., Gallo, L., & Urry, C. M. (2015). THE DISCOVERY OF THE FIRST “CHANGING LOOK” QUASAR: NEW INSIGHTS INTO THE PHYSICS AND PHENOMENOLOGY OF ACTIVE GALACTIC NUCLEI. The Astrophysical Journal. https://doi.org/10.1088/0004-637x/800/2/144
Data sources
Bibliographic data: Semantic Scholar, OpenAlex, Crossref.
Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).
Semantic Scholar’s data is described in: Kinney, R., et al. (2023). The Semantic Scholar Open Data Platform. arXiv:2301.10140.
