skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Discovery of a Mid-infrared Echo from the TDE Candidate in the Nucleus of ULIRG F01004−2237

Abstract

We present the mid-infrared (MIR) light curves (LCs) of a tidal disruption event candidate in the center of a nearby ultraluminous infrared galaxy F01004−2237 using archival WISE and NEOWISE data from 2010 to 2016. At the peak of the optical flare, F01004−2237 was IR quiescent. About three years later, its MIR fluxes have shown a steady increase, rising by 1.34 and 1.04 mag in 3.4 and 4.6 μ m up to the end of 2016. The host-subtracted MIR peak luminosity is 2–3 × 10{sup 44} erg s{sup −1}. We interpret the MIR LCs as an infrared echo, i.e., dust reprocessed emission of the optical flare. Fitting the MIR LCs using our dust model, we infer a dust torus of the size of a few parsecs at some inclined angle. The derived dust temperatures range from 590–850 K, and the warm dust mass is ∼7 M {sub ⊙}. Such a large mass implies that the dust cannot be newly formed. We also derive the UV luminosity of 4–11 × 10{sup 44} erg s{sup −1}. The inferred total IR energy is 1–2 × 10{sup 52} erg, suggesting a large dust covering factor. Finally, our dust model suggests that the long tail ofmore » the optical flare could be due to dust scattering.« less

Authors:
 [1]; ; ; ;  [2];  [3];  [4];  [5]
  1. Center for Astrophysics, Guangzhou University, Guangzhou 510006 (China)
  2. CAS Key Laboratory for Researches in Galaxies and Cosmology, University of Sciences and Technology of China, Hefei, Anhui 230026 (China)
  3. Caltech Optical Observatories, Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)
  4. IPAC, Mail Code 100-22, California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States)
  5. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
Publication Date:
OSTI Identifier:
22654476
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 841; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLACK HOLES; COVERINGS; DUSTS; EMISSION; GALAXIES; GALAXY NUCLEI; INTERMEDIATE INFRARED RADIATION; LUMINOSITY; MASS; SCATTERING; VISIBLE RADIATION

Citation Formats

Dou, Liming, Wang, Tinggui, Jiang, Ning, Yang, Chenwei, Peng, Bo, Yan, Lin, Cutri, Roc M., and Mainzer, Amy, E-mail: doulm@gzhu.edu.cn, E-mail: twang@ustc.edu.cn, E-mail: lyan@ipac.caltech.edu. Discovery of a Mid-infrared Echo from the TDE Candidate in the Nucleus of ULIRG F01004−2237. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA7130.
Dou, Liming, Wang, Tinggui, Jiang, Ning, Yang, Chenwei, Peng, Bo, Yan, Lin, Cutri, Roc M., & Mainzer, Amy, E-mail: doulm@gzhu.edu.cn, E-mail: twang@ustc.edu.cn, E-mail: lyan@ipac.caltech.edu. Discovery of a Mid-infrared Echo from the TDE Candidate in the Nucleus of ULIRG F01004−2237. United States. doi:10.3847/2041-8213/AA7130.
Dou, Liming, Wang, Tinggui, Jiang, Ning, Yang, Chenwei, Peng, Bo, Yan, Lin, Cutri, Roc M., and Mainzer, Amy, E-mail: doulm@gzhu.edu.cn, E-mail: twang@ustc.edu.cn, E-mail: lyan@ipac.caltech.edu. Sat . "Discovery of a Mid-infrared Echo from the TDE Candidate in the Nucleus of ULIRG F01004−2237". United States. doi:10.3847/2041-8213/AA7130.
@article{osti_22654476,
title = {Discovery of a Mid-infrared Echo from the TDE Candidate in the Nucleus of ULIRG F01004−2237},
author = {Dou, Liming and Wang, Tinggui and Jiang, Ning and Yang, Chenwei and Peng, Bo and Yan, Lin and Cutri, Roc M. and Mainzer, Amy, E-mail: doulm@gzhu.edu.cn, E-mail: twang@ustc.edu.cn, E-mail: lyan@ipac.caltech.edu},
abstractNote = {We present the mid-infrared (MIR) light curves (LCs) of a tidal disruption event candidate in the center of a nearby ultraluminous infrared galaxy F01004−2237 using archival WISE and NEOWISE data from 2010 to 2016. At the peak of the optical flare, F01004−2237 was IR quiescent. About three years later, its MIR fluxes have shown a steady increase, rising by 1.34 and 1.04 mag in 3.4 and 4.6 μ m up to the end of 2016. The host-subtracted MIR peak luminosity is 2–3 × 10{sup 44} erg s{sup −1}. We interpret the MIR LCs as an infrared echo, i.e., dust reprocessed emission of the optical flare. Fitting the MIR LCs using our dust model, we infer a dust torus of the size of a few parsecs at some inclined angle. The derived dust temperatures range from 590–850 K, and the warm dust mass is ∼7 M {sub ⊙}. Such a large mass implies that the dust cannot be newly formed. We also derive the UV luminosity of 4–11 × 10{sup 44} erg s{sup −1}. The inferred total IR energy is 1–2 × 10{sup 52} erg, suggesting a large dust covering factor. Finally, our dust model suggests that the long tail of the optical flare could be due to dust scattering.},
doi = {10.3847/2041-8213/AA7130},
journal = {Astrophysical Journal Letters},
number = 1,
volume = 841,
place = {United States},
year = {Sat May 20 00:00:00 EDT 2017},
month = {Sat May 20 00:00:00 EDT 2017}
}
  • In this paper, we present ground-based and Swift photometric and spectroscopic observations of the candidate tidal disruption event (TDE) ASASSN-14li, found at the centre of PGC 043234 (d ≃ 90 Mpc) by the All-Sky Automated Survey for SuperNovae (ASAS-SN). The source had a peak bolometric luminosity of L ≃ 10 44 erg s -1 and a total integrated energy of E ≃ 7 × 10 50 erg radiated over the ~6 months of observations presented. The UV/optical emission of the source is well fitted by a blackbody with roughly constant temperature of T ~ 35 000 K, while the luminositymore » declines by roughly a factor of 16 over this time. The optical/UV luminosity decline is broadly consistent with an exponential decline, L∝e -t/t0, with t 0 ≃ 60 d. ASASSN-14li also exhibits soft X-ray emission comparable in luminosity to the optical and UV emission but declining at a slower rate, and the X-ray emission now dominates. Spectra of the source show broad Balmer and helium lines in emission as well as strong blue continuum emission at all epochs. Finally, we use the discoveries of ASASSN-14li and ASASSN-14ae to estimate the TDE rate implied by ASAS-SN, finding an average rate of r ≃ 4.1 × 10 -5 yr -1 per galaxy with a 90 per cent confidence interval of (2.2–17.0) × 10 -5 yr -1 per galaxy. ASAS-SN found roughly 1 TDE for every 70 Type Ia supernovae in 2014, a rate that is much higher than that of other surveys.« less
  • We present rest-frame 15 and 24 {mu}m luminosity functions (LFs) and the corresponding star-forming LFs at z < 0.3 derived from the 5MUSES sample. Spectroscopic redshifts have been obtained for {approx}98% of the objects and the median redshift is {approx}0.12. The 5-35 {mu}m Infrared Spectrograph spectra allow us to estimate accurately the luminosities and build the LFs. Using a combination of starburst and quasar templates, we quantify the star formation (SF) and active galactic nucleus (AGN) contributions in the mid-IR spectral energy distribution. We then compute the SF LFs at 15 and 24 {mu}m, and compare with the total 15more » and 24 {mu}m LFs. When we remove the contribution of AGNs, the bright end of the LF exhibits a strong decline, consistent with the exponential cutoff of a Schechter function. Integrating the differential LF, we find that the fractional contribution by SF to the energy density is 58% at 15 {mu}m and 78% at 24 {mu}m, while it goes up to {approx}86% when we extrapolate our mid-IR results to the total IR luminosity density. We confirm that the AGNs play more important roles energetically at high luminosities. Finally, we compare our results with work at z {approx} 0.7 and confirm that evolution on both luminosity and density is required to explain the difference in the LFs at different redshifts.« less
  • We present the results of a program of optical and near-infrared spectroscopic follow-up of candidate active galactic nuclei (AGNs) selected in the mid-infrared. This survey selects both normal and obscured AGNs closely matched in luminosity across a wide range, from Seyfert galaxies with bolometric luminosities L {sub bol} ∼ 10{sup 10} L {sub ☉} to highly luminous quasars (L {sub bol} ∼ 10{sup 14} L {sub ☉}), all with redshifts ranging from 0 to 4.3. Samples of candidate AGNs were selected with mid-infrared color cuts at several different 24 μm flux density limits to ensure a range of luminosities atmore » a given redshift. The survey consists of 786 candidate AGNs and quasars, of which 672 have spectroscopic redshifts and classifications. Of these, 137 (20%) are type 1 AGNs with blue continua, 294 (44%) are type 2 objects with extinctions A{sub V} ∼> 5 toward their AGNs, 96 (14%) are AGNs with lower extinctions (A{sub V} ∼ 1), and 145 (22%) have redshifts, but no clear signs of AGN activity in their spectra. Of the survey objects 50% have L {sub bol} > 10{sup 12} L {sub ☉}, in the quasar regime. We present composite spectra for type 2 quasars and objects with no signs of AGN activity in their spectra. We also discuss the mid-infrared—emission-line luminosity correlation and present the results of cross correlations with serendipitous X-ray and radio sources. The results show that: (1) obscured objects dominate the overall AGN population, (2) mid-infrared selected AGN candidates exist which lack AGN signatures in their optical spectra but have AGN-like X-ray or radio counterparts, and (3) X-ray and optical classifications of obscured and unobscured AGNs often differ.« less
  • Images of the gravitational lens system candidate 2237+030 in three colors are obtained under seeings of 0.6-0.9 arcsec. The excellent seeing and the 0.2 arcsec per pixel scale permit the resolution of the system into four stellar components and the galaxy nuclear component in a cross pattern. The positions and intensities of the quasar-candidate components are derived using an iterative point-spread-function subtraction procedure. The largest separation of the components is 1.8 arcsec. Variations of g-i colors of up to 0.3 mag are seen among the quasar-candidate components. This can be interpreted as variable absorption through the galaxy. An estimate ofmore » the true luminosity ratios of the four components is made. Detailed morphological study of the galaxy shows that the galaxy is a well-developed barred spiral with an inner ring and a small bulge. Standard de Vaucouleurs and exponential disk laws are fitted to the brightness profile. 21 references.« less
  • We report on the properties of pre-main-sequence objects in the Taurus molecular clouds as observed in seven mid- and far-infrared bands with the Spitzer Space Telescope. There are 215 previously identified members of the Taurus star-forming region in our {approx}44 deg{sup 2} map; these members exhibit a range of Spitzer colors that we take to define young stars still surrounded by circumstellar dust (noting that {approx}20% of the bona fide Taurus members exhibit no detectable dust excesses). We looked for new objects in the survey field with similar Spitzer properties, aided by extensive optical, X-ray, and ultraviolet imaging, and foundmore » 148 new candidate members of Taurus. We have obtained follow-up spectroscopy for about half the candidate sample, thus far confirming 34 new members, three probable new members, and 10 possible new members, an increase of 15%-20% in Taurus members. Of the objects for which we have spectroscopy, seven are now confirmed extragalactic objects, and one is a background Be star. The remaining 93 candidate objects await additional analysis and/or data to be confirmed or rejected as Taurus members. Most of the new members are Class II M stars and are located along the same cloud filaments as the previously identified Taurus members. Among non-members with Spitzer colors similar to young, dusty stars are evolved Be stars, planetary nebulae, carbon stars, galaxies, and active galactic nuclei.« less