A Population of Short-Period Variable Quasars from PTF as Supermassive Black Hole Binary Candidates

Supermassive black hole binaries (SMBHBs) at sub-parsec separations should be common in galactic nuclei, as a result of frequent galaxy mergers. Hydrodynamical simulations of circumbinary discs predict strong periodic modulation of the mass accretion rate on time-scales comparable to the orbital period of the binary. As a result, SMBHBs may be recognized by the periodic modulation of their brightness. We conducted a statistical search for periodic variability in a sample of 35,383 spectroscopically confirmed quasars in the photometric database of the Palomar Transient Factory (PTF). We analysed Lomb-Scargle periodograms and assessed the significance of our findings by modeling each individual quasar's variability as a damped random walk (DRW). We identified 50 quasars with significant periodicity beyond the DRW model, typically with short periods of a few hundred days. We find 33 of these to remain significant after a re-analysis of their periodograms including additional optical data from the intermediate-PTF and the Catalina Real-Time Transient Survey (CRTS). Assuming that the observed periods correspond to the redshifted orbital periods of SMBHBs, we conclude that our findings are consistent with a population of unequal-mass SMBHBs, with a typical mass ratio as low as q = M2/M1 ~ 0.01.Comment: MNRAS (accepted), new section 4.

Transit analysis of the CoRoT-5, CoRoT-8, CoRoT-12, CoRoT-18, CoRoT-20, and CoRoT-27 systems with combined ground- and space-based photometry

We have initiated a dedicated project to follow-up with ground-based photometry the transiting planets discovered by CoRoT in order to refine the orbital elements, constrain their physical parameters and search for additional bodies in the system. From 2012 September to 2016 December we carried out 16 transit observations of six CoRoT planets (CoRoT-5b, CoRoT-8b, CoRoT-12b, CoRoT-18b, CoRoT-20b, and CoRoT-27b) at three observatories located in Germany and Spain. These observations took place between 5 and 9 yr after the planet's discovery, which has allowed us to place stringent constraints on the planetary ephemeris. In five cases we obtained light curves with a deviation of the mid-transit time of up to ~115min from the predictions. We refined the ephemeris in all these cases and reduced the uncertainties of the orbital periods by factors between 1.2 and 33. In most cases our determined physical properties for individual systems are in agreement with values reported in previous studies. In one case, CoRoT-27b, we could not detect any transit event in the predicted transit window.Comment: 17 pages, 23 figures, 15 tables, accepted by MNRA

Commissioning of the tuned DC readout at GEO 600

Recent experimental results from GEO600 operating with a DC readout and a tuned signal recycling cavity are reported. Compared to the S5/Astrowatch setup, two major changes in the configuration have been implemented: the control readout to keep the interferometer on the dark fringe is changed from heterodyne to homodyne readout and the signal recycling cavity is shifted from a 550 Hz detuning to a 0 Hz detuning (also called tuned). As preliminary experiments showed, the tuned DC readout sensitivity is similar to the heterodyne one. To take advantage of the new DC readout detection scheme, an Output Mode Cleaner (OMC) has to be installed. The design, building and testing of the GEO OMC, which consists of a 4 mirrors monolithic ring cavity, will also be presented in this article.Science and Technology Facilities Council (STFC)BMBFMax Planck Society (MPG)State of Lower Saxony in GermanyEuropean Gravitational Observatory (EGO)DFG/SFB/Transregio

Control and automatic alignment of the output mode cleaner of GEO 600

The implementation of a mode cleaner at the output port of the GEO 600 gravitational wave detector will be part of the upcoming transition from GEO 600 to GEO-HF. Part of the transition will be the move from a heterodyne readout to a DC readout scheme. DC readout performance will be limited by higher order optical modes and control sidebands present at the output port. For optimum performance of DC readout an output mode cleaner (OMC) will clean the output beam of these contributions. Inclusion of an OMC will introduce new noise sources whose magnitudes needed to be estimated and for which new control systems will be needed. In this article we set requirements on the performance of these control systems and investigate the simulated performance of different designs.Science and Technology Facilities Council (STFC)BMBFMax Planck Society (MPG)State of Lower Saxony in GermanyEuropean Gravitational Observatory (EGO)DFG/SFB/Transregio

WASP-14 b: Transit Timing analysis of 19 light curves

Although WASP-14 b is one of the most massive and densest exoplanets on a tight and eccentric orbit, it has never been a target of photometric follow-up monitoring or dedicated observing campaigns. We report on new photometric transit observations of WASP-14 b obtained within the framework of "Transit Timing Variations @ Young Exoplanet Transit Initiative" (TTV@YETI). We collected 19 light-curves of 13 individual transit events using six telescopes located in five observatories distributed in Europe and Asia. From light curve modelling, we determined the planetary, stellar, and geometrical properties of the system and found them in agreement with the values from the discovery paper. A test of the robustness of the transit times revealed that in case of a non-reproducible transit shape the uncertainties may be underestimated even with a wavelet-based error estimation methods. For the timing analysis we included two publicly available transit times from 2007 and 2009. The long observation period of seven years (2007-2013) allowed us to refine the transit ephemeris. We derived an orbital period 1.2 s longer and 10 times more precise than the one given in the discovery paper. We found no significant periodic signal in the timing-residuals and, hence, no evidence for TTV in the system.Comment: 12 pages, 10 figures, 7 table

Kajian Persebaran Lalu Lintas Akibat Pembongkaran Jembatan Soekarno Hatta

Dengan memperhatikan kinerja jaringan jalan satu arah pada lingkar Universitas Brawijaya yang meliputi Jl. Soekarno Hatta, Jl. Mayjen Panjaitan, Jl. Bogor, Jl. Veteran, Jl. Sumbersari-Gajayana, Jl. MT Haryono, Jl. Bunga Coklat-Pisang Kipas, Jl. MT Haryono XIII (sebelah Polsek), Jl. Bunga Cengkeh, Jl. Dewandaru, Jl. Kumis Kucing, dan Jl. Cendanadi Kota Malang yang semakin ramai saat akhir pekan, maka diperlukannya upaya untuk menganalisis dan mencari solusi yang diperlukan agar dampak yang terjadi dapat diminimalisir. Skripsi ini bertujuan untuk mengetahui distribusi perjalanan pada lingkar Universitas Brawijaya pada saat keadaan arus lalu lintas satu arah dan membuat skenario pengaturan lalu lintas akibat pembongkaran jembatan rangka Soekarno Hatta dan masa pembangunan jembatan yang baru. Kajian yang dilakukan berupa distribusi kendaraan,analisa kinerja ruas, simpang dan jalinan serta membuat skenario pengaturan lalu lintas agar dapat memberi solusi dan mengurangi terjadinya kemacetan pada saat pembongkaran jembatan rangka Soekarno Hatta danmasa pembangunan jembatan yang baru. Data penelitian didapat dengan melakukan survei distribusi kendaraan dan survei traffic counting pada hari Jumat pukul 06.00-08.00 WIB dan 15.00-17.00 WIB dengan lokasi jaringan jalan satuarahpada lingkar Universitas Brawijaya. Analisis kinerja simpang dan ruas mengacu pada MKJI 1997, sedangkan untuk skenario pengaturan lalu lintas mengacu referensi terkait yaitu mengenai optimasi waktu siklus dan geometri. Sehingga diperoleh tingkat pelayanan pada masing-masing jaringan jalan di sekitar kawasan tersebut, kemudian diambil 2 skenario yang direkomendasikan karena memiliki tingkat kinerja jalan yang lebih baikdan memiliki tingkat pengaturan lalu lintas yang relatif lebih mudah dibanding skenario yang lain. Skenario yang direkomendasikan yaitu skenario 1 dan skenario 2. Hasil yang diperoleh dari skenario 1 yaitu ruas Soekarno Hatta (arah ke Universitas Brawijaya) dengan tingkat pelayanan A dengan DS sebesar 0,34;ruas Soekarno Hatta (arah ke Blimbing) dengan tingkat pelayanan C dengan DS sebesar 0,72; ruas Soekarno Hatta (ruas pada jembatan beton) dengan tingkat pelayanan D dengan DS sebesar 0,91; ruas Bunga Cengkeh dengan tingkat pelayanan B dengan DS sebesar 0,36; ruas Dewandaru dengan tingkat pelayanan A dengan DS sebesar 0,32; ruas Cendana dengan tingkat pelayanan A dengan DS sebesar 0,06; ruas Bunga Coklat-Pisang Kipas dengan tingkat pelayanan F dengan DS sebesar 1,23; ruas MT Haryono XIII (sebelahPolsek) dengan tingkat pelayanan F dengan DS sebesar 1,23; simpang Soekarno Hatta-Bunga Coklat dengan tingkat pelayanan F dengan tundaan sebesar 339,02 detik, simpang MT Haryono-Soekarno Hatta dengan tingkat pelayanan F dengan tundaan sebesar 711,98 detik; simpang Dewandaru dengan tingkat pelayanan B dengan tundaan sebesar 13,31 detik, simpang Kumis Kucing dengan tingkat pelayanan B dengan tundaan sebesar 6,53 detik, simpang Cendana dengan tingkat pelayanan A dengan tundaan sebesar 5,00 detik. Sedangkan hasil yang diperoleh dari skenario 2 yaitu dengan hasil ruas Soekarno Hatta (arah ke Universitas Brawijaya) dengan tingkat pelayanan A dengan DS sebesar 0,34; ruas Soekarno Hatta (arah ke Blimbing) dengan tingkat pelayanan C dengan DS sebesar 0,72; ruas Soekarno Hatta (ruas pada jembatan beton) dengan tingkat pelayanan D dengan DS sebesar 0,91; ruas Bunga Cengkeh dengan tingkat pelayanan C dengan DS sebesar 0,68; ruas Dewandaru dengan tingkat pelayanan F dengan DS sebesar 1,55; ruas Cendana dengan tingkat pelayanan F dengan DS sebesar 1,67; ruas Bunga Coklat-Pisang Kipas dengan tingkat pelayanan B dengan DS sebesar 0,42; ruas MT Haryono XIII (sebelah Polsek) dengan tingkat pelayanan A dengan DS sebesar 0,09; simpang Soekarno Hatta-Bunga Coklat dengan tingkat pelayanan F dengan tundaan sebesar 394,86 detik, simpang MT Haryono-Soekarno Hatta dengan tingkat pelayanan F dengan tundaan sebesar 647,86 detik, simpang Dewandaru dengan tingkat pelayanan F dengan tundaan sebesar 829,39 detik, simpang Kumis Kucing dengan tingkat pelayanan B dengan tundaan sebesar 7,90 detik, simpang Cendana dengan tingkat pelayanan B dengan tundaan sebesar 14,40 detik

Variability of young stars: Determination of rotational periods of weak-line T Tauri stars in the Cepheus-Cassiopeia star-forming region

We report on observation and determination of rotational periods of ten weak-line T Tauri stars in the Cepheus-Cassiopeia star-forming region. Observations were carried out with the Cassegrain-Teleskop-Kamera (CTK) at University Observatory Jena between 2007 June and 2008 May. The periods obtained range between 0.49 d and 5.7 d, typical for weak-line and post T Tauri stars.Comment: 11 pages, 26 figures, accepted to be published in A

False Positive Anti-Topoisomerase I (Scl-70) Antibody Results in Clinical Practice: A Case Series From a Scleroderma Referral Center

PURPOSE: To determine if some patients who tested positive for anti-Scl-70 antibody in clinical practice, but did not have classifiable systemic sclerosis, were negative for anti-Scl-70 antibody by the more specific immunodiffusion method of testing. METHODS: Patients evaluated by a rheumatologist at a Scleroderma referral center who had tested positive for anti-Scl-70 antibody prior to referral, but did not have classifiable SSc based on clinical criteria, were invited to undergo testing for anti-Scl-70 antibody by immunodiffusion. Patient demographics and clinical features were recorded at the time of their evaluation, and diagnostic testing results were reviewed using the medical records. RESULTS: 52 patients were enrolled over an 8-year period, with 48 (92.3%) testing negative and 4 (7.7%) testing positive for anti-Scl-70 antibody by immunodiffusion. Of the 48 patients who tested negative, 18 (37.5%) tested negative for ANA by indirect immunofluorescence, 33 (68.8%) did not have Raynaud\u27s phenomenon, and 43 (89.6%) had ≤1 clinical criteria items based on the 2013 ACR/EULAR SSc classification criteria. Nevertheless, 21 (43.8%) patients who were negative for anti-Scl-70 antibody by immunodiffusion had undergone a chest CT and 14 (29.2%) had undergone an echocardiogram. A total of 23 patients had at least one follow up clinic visit. 3 out of 4 patients who were positive for anti-Scl-70 antibody by immunodiffusion, but none of the 19 patients who tested negative by immunodiffusion, developed sufficient criteria during follow up to be classified as SSc. CONCLUSION: Assays for anti-Scl-70 antibody in commercial laboratories that are commonly utilized in clinical practice can produce false positive results. These results can lead to angst for patients, as well as unnecessary referrals and diagnostic evaluations