Browsing by Author "Guo, Zhen"

Now showing items 1-11 of 11

    • Analysis of physical processes in eruptive YSOs with near infrared spectra and multi-wavelength light curves 

      Guo, Zhen; Lucas, P. W.; Contreras Pena, Carlos; Smith, L. C.; Morris, C.; Kurtev, R. G.; Borissova, J.; Alonso-García, J.; Minniti, D.; Chené, A. -N.; Kumar, M. S. N.; Garatti, A. Caratti o; Froebrich, D. (2021-03-26)
      The decade-long Vista Variables in the Via Lactea (VVV) survey has detected numerous highly variable young stellar objects (YSOs). We present a study of 61 highly variable VVV YSOs (Delta Ks = 1-5 mag), combining near ...

    • The JCMT Transient Survey: Four-year Summary of Monitoring the Submillimeter Variability of Protostars 

      Lee, Yong-Hee; Johnstone, Doug; Lee, Jeong-Eun; Herczeg, Gregory; Mairs, Steve; Contreras-Peña, Carlos; Hatchell, Jennifer; Naylor, Tim; Bell, Graham S.; Bourke, Tyler L.; Broughton, Colton; Francis, Logan; Gupta, Aashish; Harsono, Daniel; Liu, Sheng-Yuan; Park, Geumsook; Plovie, Spencer; Moriarty-Schieven, Gerald H.; Scholz, Aleks; Sharma, Tanvi; Teixeira, Paula Stella; Wang, Yao-Te; Aikawa, Yuri; Bower, Geoffrey C.; Chen, Huei-Ru Vivien; Bae, Jaehan; Baek, Giseon; Chapman, Scott; Chen, Wen Ping; Du, Fujun; Dutta, Somnath; Forbrich, Jan; Guo, Zhen; Inutsuka, Shu-ichiro; Kang, Miju; Kirk, Helen; Kuan, Yi-Jehng; Kwon, Woojin; Lai, Shih-Ping; Lalchand, Bhavana; Lane, James M. M.; Lee, Chin-Fei; Liu, Tie; Morata, Oscar; Pearson, Samuel; Pon, Andy; Sahu, Dipen; Shang, Hsien; Stamatellos, Dimitris; Tang, Shih-Yun; Xu, Ziyan; Yoo, Hyunju (2021-10-21)
      We present the four-year survey results of monthly submillimeter monitoring of eight nearby ($<500 $pc) star-forming regions by the JCMT Transient Survey. We apply the Lomb-Scargle Periodogram technique to search for and ...

    • Large amplitude periodic outbursts and long period variables in the VVV VIRAC2-$β$ database 

      Guo, Zhen; Lucas, P. W.; Smith, L. C.; Clarke, C.; Peña, C. Contreras; Bayo, A.; Briceño, C.; Elias, J.; Kurtev, R. G.; Borissova, J.; Alonso-García, J.; Minniti, D.; Catelan, M.; Nikzat, F.; Morris, C.; Miller, N. (2022-03-21)
      The VISTA Variables in the Via Lactea (VVV) survey obtained near-infrared photometry toward the Galactic bulge and the southern disc plane for a decade (2010 - 2019). We designed a modified Lomb-Scargle method to search ...

    • Multiwavelength detection of an ongoing FUOr-type outburst on a low-mass YSO 

      Guo, Zhen; Lucas, P. W.; Kurtev, R. G.; Borissova, J.; Elbakyan, V.; Morris, C.; Bayo, A.; Smith, L.; Garatti, A. Caratti o; Peña, C. Contreras; Minniti, D.; Jose, J.; Ashraf, M.; Alonso-García, J; Miller, N.; Muthu, H. D. S. (2024-03-01)
      During the pre-main-sequence evolution, Young Stellar Objects (YSOs) assemble most of their mass during the episodic accretion process. The rarely seen FUOr-type events are valuable laboratories to investigate the outbursting ...

    • On the incidence of episodic accretion in Class I YSOs from VVV 

      Peña, Carlos Contreras; Lucas, Philip W.; Guo, Zhen; Smith, Leigh (2024-02-01)
      Episodic accretion is one of the competing models to explain the observed luminosity spread in young stellar clusters. These short-lived high accretion events could also have a strong impact on planet formation. Observations ...

    • Search for brown dwarfs in IC 1396 with Subaru HSC: interpreting the impact of environmental factors on substellar population 

      Gupta, Saumya; Jose, Jessy; Das, Swagat R; Guo, Zhen; Damian, Belinda; Prakash, Prem; Samal, Manash R (2024-03-01)
      Young stellar clusters are predominantly the hub of star formation and hence, ideal to perform comprehensive studies over the least explored substellar regime. Various unanswered questions like the mass distribution in ...

    • Short and long term near-infrared spectroscopic variability of eruptive protostars from VVV 

      Guo, Zhen; Lucas, P. W.; Peña, C. Contreras; Kurtev, R. G.; Smith, L. C.; Borissova, J.; Alonso-García, J.; Minniti, D.; Garatti, A. Caratti o; Froebrich, Dirk (2020-02-01)
      Numerous eruptive variable young stellar objects (YSOs), mostly Class I systems, were recently detected by the near-infrared Vista Variables in the Via Lactea (VVV) survey. We present an exploratory near-infrared spectroscopic ...

    • Spectroscopic confirmation of high-amplitude eruptive YSOs and dipping giants from the VVV survey 

      Guo, Zhen; Lucas, P. W.; Kurtev, R.; Borissova, J.; Peña, C. Contreras; Yurchenko, S. N.; Smith, L. C.; Minniti, D.; Saito, R. K.; Bayo, A.; Catelan, M.; Alonso-García, Javier; Garatti, A. Caratti o; Morris, C.; Froebrich, D.; Tennyson, J.; Maucó, K.; Aguayo, A.; Miller, N.; Muthu, H. D. S. (2024-02-01)
      During the pre-main-sequence (pre-MS) evolution stage of a star, significant amounts of stellar mass are accreted during episodic accretion events, such as multidecade FUor-type outbursts. Here, we present a near-infrared ...

    • Twenty-five Years of Accretion onto the Classical T Tauri Star TW Hya 

      Herczeg, Gregory J.; Chen, Yuguang; Donati, Jean-Francois; Dupree, Andrea K.; Walter, Frederick M.; Hillenbrand, Lynne A.; Johns-Krull, Christopher M.; Manara, Carlo F.; Günther, Hans Moritz; Fang, Min; Schneider, P. Christian; Valenti, Jeff A.; Alencar, Silvia H. P.; Venuti, Laura; Alcalá, Juan Manuel; Frasca, Antonio; Arulanantham, Nicole; Linsky, Jeffrey L.; Bouvier, Jerome; Brickhouse, Nancy S.; Calvet, Nuria; Espaillat, Catherine C.; Campbell-White, Justyn; Carpenter, John M.; Chang, Seok-Jun; Cruz, Kelle L.; Dahm, S. E.; Eislöffel, Jochen; Edwards, Suzan; Fischer, William J.; Guo, Zhen; Henning, Thomas; Ji, Tao; Jose, Jessy; Kastner, Joel H.; Launhardt, Ralf; Principe, David A.; Robinson, Connor E.; Serna, Javier; Siwak, Michal; Sterzik, Michael F.; Takasao, Shinsuke (2023-10-12)
      Accretion plays a central role in the physics that governs the evolution and dispersal of protoplanetary disks. The primary goal of this paper is to analyze the stability over time of the mass accretion rate onto TW Hya, ...

    • Variable stars in the VVV globular clusters. II. NGC6441, NGC6569, NGC6626 (M28), NGC6656 (M22), 2MASS-GC02, and Terzan10 

      Alonso-García, Javier; Smith, Leigh C.; Catelan, Márcio; Minniti, Dante; Navarrete, Camila; Borissova, Jura; Carballo-Bello, Julio A.; Ramos, Rodrigo Contreras; Fernández-Trincado, José G.; Lopes, Carlos E. Ferreira; Gran, Felipe; Garro, Elisa R.; Geisler, Doug; Guo, Zhen; Hempel, Maren; Kerins, Eamonn; Lucas, Philip W.; Palma, Tali; Ramírez, Karla Peña; Alegría, Sebastián Ramírez; Saito, Roberto K. (2021-07-12)
      Context. The Galactic globular clusters (GGCs) located in the inner regions of the Milky Way suffer from high extinction that makes their observation challenging. High densities of field stars in their surroundings complicate ...

    • VVV-WIT-12 and Its Fashionable Nebula: A 4 yr Long-period Young Stellar Object with a Light Echo? 

      Saito, Roberto K.; Stecklum, Bringfried; Minniti, Dante; Lucas, Philip W.; Guo, Zhen; Smith, Leigh C.; Fraga, Luciano; Navarete, Felipe; Beamin, Juan Carlos; Morris, Calum (2023-11-14)
      We report the serendipitous discovery of VVV-WIT-12, an unusual variable source that seems to induce variability in its surrounding nebula. The source belongs to the rare objects that we call WITs (short for What Is This?) ...