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astro-ph.SR · Solar and Stellar Astrophysicsastro-ph.IM · Instrumentation and Methods for Astrophysicsastro-ph.EP · Earth and Planetary Astrophysics

A fixed W2/W1 ratio fits added light in selected 2018–2022 ASASSN-21qj images under the stated errors

We test whether one ratio of added W2 light to added W1 light fits selected public NEOWISE images of ASASSN-21qj. This is a known infrared event with a later optical eclipse. We preserve 192 selected intensity cutouts. Ninety exposure pairs pass image registration. We combine valid pixels in 12 visits, measure a 13.75 arcsec aperture, and calibrate with 22 fixed field stars. Two scan-season baselines from 2017 define the added light in ten 2018–2022 visits. The fit includes paired jackknife errors, shared baseline covariance, and a predictive field-star error allowance. The best W2/W1 slope is 2.353, with a 95% profile interval of 2.158–2.569 in per-band Vega units. The fit gives Q = 8.986 for nine reference degrees of freedom. The conditional simulation p value is 0.411 from 3000 samples. A two-phase fit gives a late/early slope ratio of 0.891, with a 95% interval of 0.752–1.055. Halving the field standard deviations gives a chi-square reference p value of 0.0195. The inference depends on the error model. The aperture includes a close star, and the artificial-source tests do not bound the real telescope response. The data do not establish physical cooling, a collision, or a new planet. We release all selected images, request records, hashes, fluxes, covariance, simulations, response checks, figures, and offline code. A separate full reduction reproduces 19 result files and all compared numerical arrays exactly.

ASASSN-21qj · NEOWISE · infrared variability · aperture photometry · missing pixels · field calibration · shared baseline covariance · conditional color test · reproducible dataset

Admitted 2 citing publications

References

17
  1. usesTen ASASSN-21qj infrared visits give a constant-colour p value of 0.028 under the stated error model sci:sha256:378e7fb1a635c429fc297c6e64f6b2a76c2e622b6e3dfac17e45603bf7272413

    This catalog color test motivates the new image measurements. The new test uses a smaller exposure set, two 2017 baselines, and a different error model. It is not an exact repetition of that test.

  2. usesTwo 2019 W2 difference images place the added light closer to ASASSN-21qj than to its 3.7 arcsec neighbor sci:sha256:643d6cad3305a84eb0bffeb9bfce2abf789f5f1d8251894f0413510d79dad9ab

    We reuse verified Gaia and AllWISE tables, some IRSA image bytes, and MIT code for field selection, proper motion, and reference-star image fits. We add W1/W2 visit images and aperture color tests.

  3. usesThe blended ASASSN-21qj source has infrared flux near its earlier level in three 2023–2024 NEOWISE visits sci:sha256:2111d70dce9993c8de3f8feda9b58c62a884ff88a94a03826971209354727b18

    This work supplied the target and field source tables, query records, parser, and catalog quality rules through the later image study.

  4. doi:10.1038/s41586-023-06573-9

    This event study proposes a planetary collision and reports the infrared and optical behavior. Our two-band test does not identify a physical cause.

  5. doi:10.1038/s41586-023-06874-z

    This correction identifies the independent event study.

  6. doi:10.3847/1538-4357/ace629

    This independent event study proposes a comet breakup. It also gives the optical event dates used to define the restricted tests.

  7. usesdoi:10.26131/IRSA147

    The final NEOWISE single-exposure image archive supplies the original W1 and W2 intensity cutouts. All 192 selected files and request records are preserved.

  8. usesdoi:10.26131/IRSA144

    The NEOWISE source table supplies exposure identifiers and quality values. Its source magnitudes are used only for selection and the stated catalog comparison.

  9. usesdoi:10.26131/IRSA1

    AllWISE supplies field-star selection values, reference magnitudes, and sky-annulus neighbor masks.

  10. usesdoi:10.5270/esa-qa4lep3

    Gaia DR3 supplies target and field positions, proper motions, and reference quality values.

  11. doi:10.1051/0004-6361/202243940

    This paper describes Gaia DR3.

  12. doi:10.1088/0004-637X/792/1/30

    This paper describes the NEOWISE reactivation mission.

  13. doi:10.1088/0004-6256/140/6/1868

    This paper describes WISE.

  14. usesdoi:10.1038/s41586-020-2649-2

    NumPy supplies numerical arrays and linear algebra.

  15. usesdoi:10.1038/s41592-019-0686-2

    SciPy supplies interpolation, optimization, and statistical functions.

  16. usesdoi:10.1051/0004-6361/201322068

    Astropy supplies FITS, time, and sky-coordinate operations.

  17. usesdoi:10.1109/MCSE.2007.55

    Matplotlib makes the figures.

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