Year: 2019
Type: article
Abstract: Quasar microlensing serves as a unique probe of discrete objects within galaxies and galaxy clusters. Recent advancement of the technique shows that it can constrain planet-scale objects beyond our native galaxy by studying their induced microlensing signatures, the energy shift of emission lines originating in the vicinity of the black hole of high redshift background quasars. We employ this technique to exert effective constraints on the planet-mass object distribution within two additional lens systems, Q J0158−4325 (z l = 0.317) and SDSS J1004+4112 (z l = 0.68), using Chandra observations of the two gravitationally lensed quasars. The observed variations of the emission line peak energy can be explained as microlensing of the FeKα emission region induced by planet-mass microlenses. To corroborate this, we perform microlensing simulations to determine the probability of a caustic transiting the source region and compare this with the observed line shift rates. Our analysis yields constraints on the substellar population, with masses ranging from Moon (10−8 M ⊙) to Jupiter (10−3 M ⊙) sized bodies, within these galaxy or cluster scale structures, with total mass fractions of ∼3 × 10−4 and ∼1 × 10−4 with respect to halo mass for Q J0158−4325 and SDSS J1004+4112, respectively. Our analysis suggests that unbound planet-mass objects are universal in galaxies, and we surmise the objects to be either free-floating planets or primordial black holes. We present the first ever constraints on the substellar mass distribution in the intracluster light of a galaxy cluster. Our results provide the most stringent limit on the mass fraction of primordial black holes at the mass range.
Source: The Astrophysical Journal
Authors: Saloni Bhatiani, Xinyu Dai, Eduardo Guerras
Institution: University of Oklahoma
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: Collaborative Research: Redshift Measurements of the Swift Serendipitous Cluster Survey, A KEY QUESTION IN ASTROPHYSICS IS TO CONSTRAIN THE EVOLUTION OF THE LARGEST GRAVITATIONALLY BOUND STRUCTURES IN THE UNIVERSE. THE SERENDIPITOUS OBSERVATIONS OF SWIFT-XRT FORM AN EXCELLENT MEDIUM-DEEP AND WIDE SOFT X-RAY SURVEY WITH A SKY AREA OF ~160 SQUARE DEGREES AT THE FLUX LIMIT OF 5E-15 ERG/S/CM^2. THIS SURVEY IS ABOUT AN ORDER OF MAGNITUDE DEEPER THAN PREVIOUS SURVEYS OF SIMILAR AREAS AND AN ORDER OF MAGNITUDE WIDER THAN PREVIOUS SURVEYS OF SIMILAR DEPTH. IT IS COMPARABLE TO THE PLANNED EROSITA DEEP SURVEY BUT ALREADY WITH THE DATA SEVERAL YEARS AHEAD. THE UNIQUE COMBINATION OF THE SURVEY AREA AND DEPTH ENABLES IT TO FILL IN THE GAP BETWEEN THE DEEP PENCIL BEAM SURVEYS (SUCH AS THE CHANDRA DEEP FIELDS) AND THE SHALLOW WIDE AREA SURVEYS MEASURED WITH ROSAT. WITH IT WE WILL PLACE INDEPENDENT AND COMPLEMENTARY MEASUREMENTS ON THE NUMBER COUNTS AND LUMINOSITY FUNCTIONS OF X-RAY SOURCES. IT HAS BEEN PROVED THAT THIS SURVEY IS EXCELLENT FOR X-RAY SELECTED GALAXY CLUSTER SURVEYS BASED ON OUR INITIAL ANALYSIS OF 1/4 OF THE FIELDS AND OTHER INDEPENDENT STUDIES. THE HIGHEST PRIORITY GOAL IS TO PRODUCE THE LARGEST UNIFORMLY SELECTED CATALOG OF X-RAY SELECTED CLUSTERS AND INCREASE THE SAMPLE OF INTERMEDIATE TO HIGH REDSHIFT CLUSTERS (Z>0.5) BY AN ORDER OF MAGNITUDE. FROM THIS CATALOG WE WILL STUDY THE EVOLUTION OF CLUSTER NUMBER COUNTS LUMINOSITY FUNCTION SCALING RELATIONS AND EVENTUALLY THE MASS FUNCTION. FOR EXAMPLE VARIOUS SMALLER SCALE SURVEYS CONCLUDED DIVERGENTLY ON THE EVOLUTION OF A KEY SCALING RELATION BETWEEN TEMPERATURE AND LUMINOSITY OF CLUSTERS. WITH THE STATISTICAL POWER FROM THIS LARGE SAMPLE WE WILL RESOLVE THE DEBATE WHETHER CLUSTERS EVOLVE SELF-SIMILARLY. THIS IS A CRUCIAL STEP IN MAPPING CLUSTER EVOLUTION AND CONSTRAINING COSMOLOGICAL MODELS. FIRST WE PROPOSE TO EXTRACT THE COMPLETE SERENDIPITOUS EXTENDED SOURCE LIST FOR ALL SWIFT-XRT DATA TO 2015. SECOND WE WILL USE OPTICAL/ IR OBSERVATIONS TO FURTHER IDENTIFY GALAXY CLUSTERS. THESE OPTICAL/IR OBSERVATIONS INCLUDE DATA FROM THE SDSS WISE AND DEEP OPTICAL FOLLOW-UP OBSERVATIONS FROM THE APO MDM MAGELLAN AND NOAO TELESCOPES. WISE WILL CONFIRM ALL Z<0.5 CLUSTERS AND A FRACTION OF Z>0.5 CLUSTERS. WE WILL USE GROUND-BASED OBSERVATIONS TO MEASURE REDSHIFTS FOR Z>0.5 CLUSTERS WITH A FOCUS OF MEASURING 1/10 OF THE SPECTROSCOPIC REDSHIFTS OF Z>0.5 CLUSTERS WITHIN THE BUDGET PERIOD. THIRD WE WILL ANALYZE OUR DEEP SUZAKU X-RAY FOLLOW-UP OBSERVATIONS OF A SAMPLE OF MEDIUM REDSHIFT CLUSTERS AND THE 1/10 BRIGHT SWIFT CLUSTERS SUITABLE FOR SPECTRAL ANALYSIS. WE WILL ALSO PERFORM STACKING ANALYSIS USING THE SWIFT DATA FOR CLUSTERS IN DIFFERENT REDSHIFT BINS TO CONSTRAIN THE EVOLUTION OF CLUSTER PROPERTIES.
OpenAlex ID: W2976252616