Reanalysis of the MACHO Constraints on PBH in the Light of Gaia DR3 Data

The recent astrometric data of hundreds of millions of stars from Gaia DR3 has allowed for a precise determination of the Milky Way rotation curve up to 28 kpc. The data suggest a rapid decline in the density of dark matter beyond 19 kpc. We fit the whole rotation curve with four components (gas, di...

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Main Authors: Juan García-Bellido, Michael Hawkins
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Universe
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Online Access:https://www.mdpi.com/2218-1997/10/12/449
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author Juan García-Bellido
Michael Hawkins
author_facet Juan García-Bellido
Michael Hawkins
author_sort Juan García-Bellido
collection DOAJ
description The recent astrometric data of hundreds of millions of stars from Gaia DR3 has allowed for a precise determination of the Milky Way rotation curve up to 28 kpc. The data suggest a rapid decline in the density of dark matter beyond 19 kpc. We fit the whole rotation curve with four components (gas, disk, bulge, and halo), and compute the microlensing optical depth to the Large Magellanic Cloud. With this model of the galaxy we reanalyse the microlensing events of the MACHO and EROS-2 Collaborations. Using the published MACHO efficiency function for the duration of their survey, together with the rate of expected events according to the new density profile, we find that the Dark Matter halo could be composed of up to 20% of massive compact halo objects for any mass between <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.001</mn></mrow></semantics></math></inline-formula> to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1</mn><mspace width="3.33333pt"></mspace><msub><mi>M</mi><mo>⊙</mo></msub></mrow></semantics></math></inline-formula>. For the EROS-2 survey, using a modified efficiency curve for consistency with the MACHO analysis, we also find compatibility with a MACHO halo, but with a tighter constraint around <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.005</mn><mspace width="3.33333pt"></mspace><msub><mi>M</mi><mo>⊙</mo></msub></mrow></semantics></math></inline-formula> where the halo fraction cannot be larger than ∼10%. This result assumes that all the lenses have the same mass. If these were distributed in an extended mass function like that of the Thermal History Model, the constraints are weakened, allowing 100% of all DM in the form of Primordial Black Holes.
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spelling doaj-art-dddc03add45b46c4a3d7e5d170d40aec2024-12-27T14:57:17ZengMDPI AGUniverse2218-19972024-12-01101244910.3390/universe10120449Reanalysis of the MACHO Constraints on PBH in the Light of Gaia DR3 DataJuan García-Bellido0Michael Hawkins1Instituto de Física Teórica UAM/CSIC, Universidad Autónoma de Madrid, Nicolás Cabrera 13, 28049 Madrid, SpainInstitute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UKThe recent astrometric data of hundreds of millions of stars from Gaia DR3 has allowed for a precise determination of the Milky Way rotation curve up to 28 kpc. The data suggest a rapid decline in the density of dark matter beyond 19 kpc. We fit the whole rotation curve with four components (gas, disk, bulge, and halo), and compute the microlensing optical depth to the Large Magellanic Cloud. With this model of the galaxy we reanalyse the microlensing events of the MACHO and EROS-2 Collaborations. Using the published MACHO efficiency function for the duration of their survey, together with the rate of expected events according to the new density profile, we find that the Dark Matter halo could be composed of up to 20% of massive compact halo objects for any mass between <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.001</mn></mrow></semantics></math></inline-formula> to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1</mn><mspace width="3.33333pt"></mspace><msub><mi>M</mi><mo>⊙</mo></msub></mrow></semantics></math></inline-formula>. For the EROS-2 survey, using a modified efficiency curve for consistency with the MACHO analysis, we also find compatibility with a MACHO halo, but with a tighter constraint around <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.005</mn><mspace width="3.33333pt"></mspace><msub><mi>M</mi><mo>⊙</mo></msub></mrow></semantics></math></inline-formula> where the halo fraction cannot be larger than ∼10%. This result assumes that all the lenses have the same mass. If these were distributed in an extended mass function like that of the Thermal History Model, the constraints are weakened, allowing 100% of all DM in the form of Primordial Black Holes.https://www.mdpi.com/2218-1997/10/12/449galactic rotation curvesGaia astrometryprimordial black holes
spellingShingle Juan García-Bellido
Michael Hawkins
Reanalysis of the MACHO Constraints on PBH in the Light of Gaia DR3 Data
Universe
galactic rotation curves
Gaia astrometry
primordial black holes
title Reanalysis of the MACHO Constraints on PBH in the Light of Gaia DR3 Data
title_full Reanalysis of the MACHO Constraints on PBH in the Light of Gaia DR3 Data
title_fullStr Reanalysis of the MACHO Constraints on PBH in the Light of Gaia DR3 Data
title_full_unstemmed Reanalysis of the MACHO Constraints on PBH in the Light of Gaia DR3 Data
title_short Reanalysis of the MACHO Constraints on PBH in the Light of Gaia DR3 Data
title_sort reanalysis of the macho constraints on pbh in the light of gaia dr3 data
topic galactic rotation curves
Gaia astrometry
primordial black holes
url https://www.mdpi.com/2218-1997/10/12/449
work_keys_str_mv AT juangarciabellido reanalysisofthemachoconstraintsonpbhinthelightofgaiadr3data
AT michaelhawkins reanalysisofthemachoconstraintsonpbhinthelightofgaiadr3data