Detection of Galactic Center source G2 at 3.8 $\mu$m during periapse passage

Abstract

We report new observations of the Galactic Center source G2 from the W. M. Keck Observatory. G2 is a dusty red object associated with gas that shows tidal interactions as it nears closest approach with the Galaxy's central black hole. Our observations, conducted as G2 passed through periapse, were designed to test the proposal that G2 is a 3 earth mass gas cloud. Such a cloud should be tidally disrupted during periapse passage. The data were obtained using the Keck II laser guide star adaptive optics system (LGSAO) and the facility near-infrared camera (NIRC2) through the K' [2.1 $\mu$m] and L' [3.8 $\mu$m] broadband filters. Several results emerge from these observations: 1) G2 has survived its closest approach to the black hole as a compact, unresolved source at L'; 2) G2's L' brightness measurements are consistent with those over the last decade; 3) G2's motion continues to be consistent with a Keplerian model. These results rule out G2 as a pure gas cloud and imply that G2 has a central star. This star has a luminosity of $\sim$30 $L_{\odot }$ and is surrounded by a large ($\sim$2.6 AU) optically thick dust shell. The differences between the L' and Br-$\gamma$ observations can be understood with a model in which L' and Br-$\gamma$ emission arises primarily from internal and external heating, respectively. We suggest that G2 is a binary star merger product and will ultimately appear similar to the B-stars that are tightly clustered around the black hole (the so-called S-star cluster).

arXiv commentAccepted by ApJ Letters, 2014 October 14

References in corpus (37)

• Comprehensive analytic formulae for stellar evolution as a function of mass and metallicity
• Measuring Distance and Properties of the Milky Way's Central Supermassive Black Hole with Stellar Orbits
• High Proper Motion Stars in the Vicinity of Sgr A*: Evidence for a Supermassive Black Hole at the Center of Our Galaxy
• Near-infrared flares from accreting gas around the supermassive black hole at the Galactic Centre
• Secular Dynamics in Hierarchical Three-Body Systems
• A Disk of Young Stars at the Galactic Center as Determined by Individual Stellar Orbits
• A gas cloud on its way towards the super-massive black hole in the Galactic Centre
• Variable Infrared Emission from the Supermassive Black Hole at the Center of the Milky Way
• Properties of the Remnant Clockwise Disk of Young Stars in the Galactic Center
• First Simultaneous NIR/X-ray Detection of a Flare from SgrA*
• A Constant Spectral Index for Sagittarius A* During Infrared/X-ray Intensity Variations
• Physics of the Galactic Center Cloud G2, on its Way towards the Super-Massive Black Hole
• StarFinder: an IDL GUI based code to analyze crowded fields with isoplanatic correcting PSF fitting
• Source-intrinsic near-infrared properties of Sgr A*: Total intensity measurements
• The Galactic Center cloud G2 and its gas streamer
• OGLE-2002-BLG-360: from a gravitational microlensing candidate to an overlooked red transient
• Simulations of the Origin and Fate of the Galactic Center Cloud G2
• Near-infrared proper motions and spectroscopy of infrared excess sources at the Galactic Center
• Pericenter passage of the gas cloud G2 in the Galactic Center
• Keck Observations of the Galactic Center Source G2: Gas Cloud or Star?
• Secular Evolution Of Binaries Near Massive Black Holes: Formation of compact binaries, merger/collision products and G2-like objects
• New observations of the gas cloud G2 in the Galactic Center
• The Galactic Center Cloud G2 -- a Young Low-Mass Star with a Stellar Wind
• Disruption of a Proto-Planetary Disk by the Black Hole at the Milky Way Centre
• Photometric Stellar Variability in the Galactic Center
• Three-Dimensional Moving-Mesh Simulations of Galactic Center Cloud G2
• The Galactic Center Weather Forecast
• Disks in the Arches cluster -- survival in a starburst environment
• Hydrodynamical simulations of a compact source scenario for the Galactic Center cloud G2
• V4332 Sagittarii: A circumstellar disc obscuring the main object
• Radio light curves during the passage of cloud G2 near Sgr A*
• Possible Origin of the G2 Cloud from the Tidal Disruption of a Known Giant Star by Sgr A*
• Dust-enshrouded star near supermassive black hole: predictions for high-eccentricity passages near low-luminosity galactic nuclei
• A star disrupted by a stellar black hole as the origin of the cloud falling toward the Galactic center
• Origin of Dust around V1309 Sco
• Simulating the effect of the Sgr A* accretion flow on the appearance of G2 after pericenter
• Theory of G2 Cloud Multi-Wavelength Emission

Cited by in corpus (74)

• The Eccentric Kozai-Lidov Effect and Its Applications
• Merging Binaries in the Galactic Center: The eccentric Kozai-Lidov mechanism with stellar evolution
• Sgr A* and General Relativity
• Radio and Millimeter Monitoring of Sgr A*: Spectrum, Variability, and Constraints on the G2 Encounter
• Unprecedented variability of Sgr A* in NIR
• Stellar transits across a magnetized accretion torus as a mechanism for plasmoid ejection
• Fifteen years of XMM-Newton and Chandra monitoring of Sgr A*: Evidence for a recent increase in the bright flaring rate
• The Fate of Binaries in the Galactic Center: The Mundane and the Exotic
• Persistent Asymmetric Structure of Sagittarius A* on Event Horizon Scales
• Evidence for periodicity in 43 year-long monitoring of NGC 5548
• A population of dust-enshrouded objects orbiting the Galactic black hole
• Hinting a dark matter nature of Sgr A* via the S-stars
• Investigating the Binarity of S0-2: Implications for its Origins and Robustness as a Probe of the Laws of Gravity around a Supermassive Black Hole
• A Cool Accretion Disk around the Galactic Centre Black Hole
• The geodesic motion of S2 and G2 as a test of the fermionic dark matter nature of our galactic core
• Monitoring the Dusty S-Cluster Object (DSO/G2) on its Orbit towards the Galactic Center Black Hole
• Kinematic Structure of the Galactic Center S-cluster
• The Hills Mechanism and the Galactic Center S-stars
• Gravitational-Wave Signatures from Compact Object Binaries in the Galactic Center
• The Post-Periapse Evolution of Galactic Center Source G1: The second case of a resolved tidal interaction with a supermassive black hole
• The Post-Pericenter Evolution of the Galactic Center Source G2
• Confusing binaries: the role of stellar binaries in biasing disk properties in the Galactic Center
• Compact Radio Sources within 30" of Sgr A*: Proper Motions, Stellar Winds and the Accretion Rate onto Sgr A*
• Clump formation through colliding stellar winds in the Galactic Centre
• Observations of Sagittarius A* during the pericenter passage of the G2 object with MAGIC
• The Galactic Center: Improved Relative Astrometry for Velocities, Accelerations, and Orbits near the Supermassive Black Hole
• The Keplerian three-body encounter I. Insights on the origin of the S-stars and the G-objects in the Galactic center
• Multiwavelength study of the flaring activity of Sgr A* in 2014 February-April
• The Galactic Center as a laboratory for theories of gravity and dark matter
• Sagittarius A* High Energy X-ray Flare Properties During NuSTAR Monitoring of the Galactic Center from 2012 to 2015
• Monitoring dusty sources in the vicinity of Sgr A*
• Nature of the Galactic centre NIR-excess sources. I. What can we learn from the continuum observations of the DSO/G2 source?
• Supernova Kicks and Dynamics of Compact Remnants in the Galactic Centre
• Polarized near-infrared light of the Dusty S-cluster Object (DSO/G2) at the Galactic Center
• A Deep Chandra View of A Candidate Parsec-Scale Jet from the Galactic Center Super-massive Black Hole
• Star Formation and Dynamics in the Galactic Centre
• Galactic Center IRS13E: Colliding Stellar Winds or an Intermediate Mass Black Hole?
• 3D adaptive mesh refinement simulations of the gas cloud G2 born within the disks of young stars in the Galactic Center
• Simultaneous Monitoring of X-ray and Radio Variability in Sagittarius A*
• Effect of an isotropic outflow from the Galactic centre on the bow-shock evolution along the orbit
• Evidence of a Decreased Binary Fraction for Massive Stars Within 20 Milliparsecs of the Supermassive Black Hole at the Galactic Center
• Stellar Populations in the Central 0.5 pc of Our Galaxy III: The Dynamical Sub-structures
• No asymmetric outflows from Sagittarius A* during the pericenter passage of the gas cloud G2
• A new bow-shock source with bipolar morphology in the vicinity of Sgr A*
• Constraining the accretion flow density profile near Sgr A* using the $L^{\prime }$-band emission of the S2 star
• Consistency of the Infrared Variability of Sgr A* over 22 years
• Using gas clouds to probe the accretion flow around SgrA*: G2's delayed pericenter passage
• The apparent tail of the Galactic center object G2/DSO
• Sgr A* and its Environment: Low Mass Star Formation, the Origin of X-ray Gas and Collimated Outflow
• Close stellar encounters at the Galactic Centre I: The effect on the observed stellar populations
• The Swansong of the Galactic Center Source X7: An Extreme Example of Tidal Evolution near the Supermassive Black Hole
• The evolution of circumstellar discs in the Galactic Centre: an application to the G-clouds
• No Microwave Flare of Sagittarius A* around the G2 Periastron Passing
• Monitoring the Galactic Centre with Australia Telescope Compact Array
• Constraints on the origins of hypervelocity stars: velocity distribution, mergers and star-formation history
• A Swift study of long-term changes in the X-ray flaring properties of Sagittarius A*
• Lobe Overflow as the Likely Cause of Pericenter Outburst in an SMBH Orbiter
• The secular evolution of discrete quasi-Keplerian systems. II. Application to a multi-mass axisymmetric disc around a supermassive black hole
• A Possible Time-Delayed Brightening of the Sgr A* Accretion Flow after the Pericenter Passage of G2 Cloud
• Eclipsing Stellar Binaries in the Galactic Center
• The G2+G2t complex as a fast and massive outflow?
• Candidate Young Stellar Objects in the S-cluster: The Kinematic Analysis of a Sub-population of the Low-mass G-objects close to Sgr A*
• 3D AMR hydrosimulations of a compact source scenario for the Galactic Centre cloud G2
• Probing the Gas Density in our Galactic Center: Moving Mesh Simulations of G2
• G2 and Sgr A*: A Cosmic Fizzle At The Galactic Center
• Enhanced Doppler Beaming for Dust-Enshrouded Objects and Pulsars in the Galactic Center
• Closing the gap: Follow-up observations of peculiar dusty objects close to Sgr A* using ERIS
• The dynamics of S-stars and G-sources orbiting a supermassive compact object made of fermionic dark matter
• The gas streamer G1-2-3 in the Galactic Center
• Detection of polarized continuum emission of the Dusty S-cluster Object (DSO/G2)
• Tidal phenomena in the Galactic Center: The curious case of X7
• Search for long-term variability of HESS J1745-290
• Black Hole Survival Guide: Searching for Stars in the Galactic Center That Endure Partial Tidal Disruption
• Variability of Sagittarius A* at 3 GHz on minute-scale with MeerKAT